Fix authentication plugin's tests in case username contains non-alphanumeric character, e.g dash

mysql-test/r/auth_named_pipe.result

 INSTALL SONAME 'auth_named_pipe';
-CREATE USER USERNAME IDENTIFIED WITH named_pipe;
+CREATE USER 'USERNAME' IDENTIFIED WITH named_pipe;
 SELECT USER(),CURRENT_USER();
 USER()	CURRENT_USER()
 USERNAME@localhost	USERNAME@%
-DROP USER USERNAME;
+DROP USER 'USERNAME';
 CREATE USER nosuchuser IDENTIFIED WITH named_pipe;
 ERROR 28000: Access denied for user 'nosuchuser'@'localhost'
 DROP USER nosuchuser;

mysql-test/t/auth_named_pipe.test

@@ -3,7 +3,7 @@
 INSTALL SONAME 'auth_named_pipe';
 
 --replace_result $USERNAME USERNAME
-eval CREATE USER $USERNAME IDENTIFIED WITH named_pipe;
+eval CREATE USER '$USERNAME' IDENTIFIED WITH named_pipe;
 # Connect using named pipe, correct username
 connect(pipe_con,localhost,$USERNAME,,,,,PIPE);
 --replace_result $USERNAME USERNAME
@@ -11,7 +11,7 @@ SELECT USER(),CURRENT_USER();
 disconnect pipe_con;
 connection default;
 --replace_result $USERNAME USERNAME
-eval DROP USER $USERNAME;
+eval DROP USER '$USERNAME';
 
 # test invalid user name
 CREATE USER nosuchuser IDENTIFIED WITH named_pipe;

plugin/auth_gssapi/mysql-test/auth_gssapi/basic.result

 INSTALL SONAME 'auth_gssapi';
-CREATE USER GSSAPI_SHORTNAME IDENTIFIED WITH gssapi;
+CREATE USER 'GSSAPI_SHORTNAME' IDENTIFIED WITH gssapi;
 SELECT USER(),CURRENT_USER();
 USER()	CURRENT_USER()
 GSSAPI_SHORTNAME@localhost	GSSAPI_SHORTNAME@%
-DROP USER GSSAPI_SHORTNAME;
+DROP USER 'GSSAPI_SHORTNAME';
 CREATE USER nosuchuser IDENTIFIED WITH gssapi;
 ERROR 28000: GSSAPI name mismatch, requested 'nosuchuser', actual name 'GSSAPI_SHORTNAME'
 DROP USER nosuchuser;

plugin/auth_gssapi/mysql-test/auth_gssapi/basic.test

@@ -4,7 +4,7 @@ INSTALL SONAME 'auth_gssapi';
 # CREATE USER without 'AS' clause
 #
 --replace_result $GSSAPI_SHORTNAME GSSAPI_SHORTNAME
-eval CREATE USER $GSSAPI_SHORTNAME IDENTIFIED WITH gssapi;
+eval CREATE USER '$GSSAPI_SHORTNAME' IDENTIFIED WITH gssapi;
 connect (con1,localhost,$GSSAPI_SHORTNAME,,);
 --replace_result $GSSAPI_SHORTNAME GSSAPI_SHORTNAME
 SELECT USER(),CURRENT_USER();
@@ -12,7 +12,7 @@ disconnect con1;
 
 connection default;
 --replace_result $GSSAPI_SHORTNAME GSSAPI_SHORTNAME
-eval DROP USER $GSSAPI_SHORTNAME;
+eval DROP USER '$GSSAPI_SHORTNAME';
 
 CREATE USER nosuchuser IDENTIFIED WITH gssapi;
 --disable_query_log