MDEV-25894: support AIX as a platform in mtr

Add fixed for tests mysqld--help,aix.rdiff and sysvars_server_notembedded,aix.rdiff

AIX couldn't compile in embedded mode so leaving sysvars_server_embedded
for later (if required).

mysql-test/include/platform.combinations

 [win]
 
+[aix]
+
 [unix]
 

mysql-test/lib/My/Platform.pm

@@ -22,7 +22,7 @@ use File::Basename;
 use File::Path;
 
 use base qw(Exporter);
-our @EXPORT= qw(IS_CYGWIN IS_WINDOWS IS_WIN32PERL
+our @EXPORT= qw(IS_CYGWIN IS_WINDOWS IS_WIN32PERL IS_AIX
 		native_path posix_path mixed_path
                 check_socket_path_length process_alive open_for_append);
 
@@ -54,6 +54,15 @@ BEGIN {
   }
 }
 
+BEGIN {
+  if ($^O eq "aix") {
+    eval 'sub IS_AIX { 1 }';
+  }
+  else {
+    eval 'sub IS_AIX { 0 }';
+  }
+}
+
 
 #
 # native_path

mysql-test/suite.pm

@@ -17,7 +17,13 @@ sub skip_combinations {
                 unless $ENV{DEBUG_KEY_MANAGEMENT_SO};
 
   # don't run tests for the wrong platform
-  $skip{'include/platform.combinations'} = [ (IS_WINDOWS) ? 'unix' : 'win' ];
+  if (IS_WINDOWS) {
+    $skip{'include/platform.combinations'} = [ 'aix', 'unix' ];
+  } elsif (IS_AIX) {
+    $skip{'include/platform.combinations'} = [ 'win', 'unix' ];
+  } else {
+    $skip{'include/platform.combinations'} = [ 'aix', 'win' ];
+  }
 
   $skip{'include/maybe_debug.combinations'} =
     [ defined $::mysqld_variables{'debug-dbug'} ? 'release' : 'debug' ];

mysql-test/suite/sys_vars/inc/sysvars_server.inc

 --source include/have_perfschema.inc
 --source include/word_size.inc
+--source include/platform.inc
 --vertical_results
 
 # need stable timestamp, because its current value is printed below

mysql-test/suite/sys_vars/r/sysvars_server_notembedded,aix.rdiff

+diff --git a/mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result b/mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result
+index bb3378139f2..ddab28508ec 100644
+--- a/mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result
++++ b/mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result
+@@ -4259,99 +4259,9 @@ VARIABLE_COMMENT	Define threads usage for handling queries
+ NUMERIC_MIN_VALUE	NULL
+ NUMERIC_MAX_VALUE	NULL
+ NUMERIC_BLOCK_SIZE	NULL
+-ENUM_VALUE_LIST	one-thread-per-connection,no-threads,pool-of-threads
++ENUM_VALUE_LIST	one-thread-per-connection,no-threads
+ READ_ONLY	YES
+ COMMAND_LINE_ARGUMENT	REQUIRED
+-VARIABLE_NAME	THREAD_POOL_DEDICATED_LISTENER
+-VARIABLE_SCOPE	GLOBAL
+-VARIABLE_TYPE	BOOLEAN
+-VARIABLE_COMMENT	If set to 1,listener thread will not pick up queries
+-NUMERIC_MIN_VALUE	NULL
+-NUMERIC_MAX_VALUE	NULL
+-NUMERIC_BLOCK_SIZE	NULL
+-ENUM_VALUE_LIST	OFF,ON
+-READ_ONLY	NO
+-COMMAND_LINE_ARGUMENT	OPTIONAL
+-VARIABLE_NAME	THREAD_POOL_EXACT_STATS
+-VARIABLE_SCOPE	GLOBAL
+-VARIABLE_TYPE	BOOLEAN
+-VARIABLE_COMMENT	If set to 1, provides better statistics in information_schema threadpool tables
+-NUMERIC_MIN_VALUE	NULL
+-NUMERIC_MAX_VALUE	NULL
+-NUMERIC_BLOCK_SIZE	NULL
+-ENUM_VALUE_LIST	OFF,ON
+-READ_ONLY	NO
+-COMMAND_LINE_ARGUMENT	OPTIONAL
+-VARIABLE_NAME	THREAD_POOL_IDLE_TIMEOUT
+-VARIABLE_SCOPE	GLOBAL
+-VARIABLE_TYPE	INT UNSIGNED
+-VARIABLE_COMMENT	Timeout in seconds for an idle thread in the thread pool.Worker thread will be shut down after timeout
+-NUMERIC_MIN_VALUE	1
+-NUMERIC_MAX_VALUE	4294967295
+-NUMERIC_BLOCK_SIZE	1
+-ENUM_VALUE_LIST	NULL
+-READ_ONLY	NO
+-COMMAND_LINE_ARGUMENT	REQUIRED
+-VARIABLE_NAME	THREAD_POOL_MAX_THREADS
+-VARIABLE_SCOPE	GLOBAL
+-VARIABLE_TYPE	INT UNSIGNED
+-VARIABLE_COMMENT	Maximum allowed number of worker threads in the thread pool
+-NUMERIC_MIN_VALUE	1
+-NUMERIC_MAX_VALUE	65536
+-NUMERIC_BLOCK_SIZE	1
+-ENUM_VALUE_LIST	NULL
+-READ_ONLY	NO
+-COMMAND_LINE_ARGUMENT	REQUIRED
+-VARIABLE_NAME	THREAD_POOL_OVERSUBSCRIBE
+-VARIABLE_SCOPE	GLOBAL
+-VARIABLE_TYPE	INT UNSIGNED
+-VARIABLE_COMMENT	How many additional active worker threads in a group are allowed.
+-NUMERIC_MIN_VALUE	1
+-NUMERIC_MAX_VALUE	1000
+-NUMERIC_BLOCK_SIZE	1
+-ENUM_VALUE_LIST	NULL
+-READ_ONLY	NO
+-COMMAND_LINE_ARGUMENT	REQUIRED
+-VARIABLE_NAME	THREAD_POOL_PRIORITY
+-VARIABLE_SCOPE	SESSION
+-VARIABLE_TYPE	ENUM
+-VARIABLE_COMMENT	Threadpool priority. High priority connections usually start executing earlier than low priority.If priority set to 'auto', the the actual priority(low or high) is determined based on whether or not connection is inside transaction.
+-NUMERIC_MIN_VALUE	NULL
+-NUMERIC_MAX_VALUE	NULL
+-NUMERIC_BLOCK_SIZE	NULL
+-ENUM_VALUE_LIST	high,low,auto
+-READ_ONLY	NO
+-COMMAND_LINE_ARGUMENT	REQUIRED
+-VARIABLE_NAME	THREAD_POOL_PRIO_KICKUP_TIMER
+-VARIABLE_SCOPE	GLOBAL
+-VARIABLE_TYPE	INT UNSIGNED
+-VARIABLE_COMMENT	The number of milliseconds before a dequeued low-priority statement is moved to the high-priority queue
+-NUMERIC_MIN_VALUE	0
+-NUMERIC_MAX_VALUE	4294967295
+-NUMERIC_BLOCK_SIZE	1
+-ENUM_VALUE_LIST	NULL
+-READ_ONLY	NO
+-COMMAND_LINE_ARGUMENT	REQUIRED
+-VARIABLE_NAME	THREAD_POOL_SIZE
+-VARIABLE_SCOPE	GLOBAL
+-VARIABLE_TYPE	INT UNSIGNED
+-VARIABLE_COMMENT	Number of thread groups in the pool. This parameter is roughly equivalent to maximum number of concurrently executing threads (threads in a waiting state do not count as executing).
+-NUMERIC_MIN_VALUE	1
+-NUMERIC_MAX_VALUE	100000
+-NUMERIC_BLOCK_SIZE	1
+-ENUM_VALUE_LIST	NULL
+-READ_ONLY	NO
+-COMMAND_LINE_ARGUMENT	REQUIRED
+-VARIABLE_NAME	THREAD_POOL_STALL_LIMIT
+-VARIABLE_SCOPE	GLOBAL
+-VARIABLE_TYPE	INT UNSIGNED
+-VARIABLE_COMMENT	Maximum query execution time in milliseconds,before an executing non-yielding thread is considered stalled.If a worker thread is stalled, additional worker thread may be created to handle remaining clients.
+-NUMERIC_MIN_VALUE	1
+-NUMERIC_MAX_VALUE	4294967295
+-NUMERIC_BLOCK_SIZE	1
+-ENUM_VALUE_LIST	NULL
+-READ_ONLY	NO
+-COMMAND_LINE_ARGUMENT	REQUIRED
+ VARIABLE_NAME	THREAD_STACK
+ VARIABLE_SCOPE	GLOBAL
+ VARIABLE_TYPE	BIGINT UNSIGNED