init_mutex_v1_t: Stop lying that the mutex parameter is const.
GCC 11.2.0 assumes that it is and could complain about any mysql_mutex_t
being uninitialized even after mysql_mutex_init() as long as
PLUGIN_PERFSCHEMA is enabled.

init_rwlock_v1_t, init_cond_v1_t: Remove untruthful const qualifiers.

Note: init_socket_v1_t is expecting that the socket fd has already
been created before PSI_SOCKET_CALL(init_socket), and therefore that
parameter really is being treated as a pointer to const.

Performance schema likely/unlikely assume that performance schema
is enabled by default, which causes a performance degradation for
default installations that doesn't have performance schema enabled.

Fixed by changing the likely/unlikely in PS to assume it's
not enabled. This can be changed by compiling with
-DPSI_ON_BY_DEFAULT

Other changes:
- Added psi_likely/psi_unlikely that is depending on
  PSI_ON_BY_DEFAULT. psi_likely() is assumed to be true
  if PS is enabled.
- Added likely/unlikely to some PS interface code.
- Moved pfs_enabled to mysys (was initialized but not used before)
- Added "if (pfs_likely(pfs_enabled))" around calls to PS to avoid
  an extra call if PS is not enabled.
- Moved checking flag_global_instrumention before other flags
  to speed up the case when PS is not enabled.

mysys/psi_noop.c:
  Fixed wrong prototype
sql/rpl_gtid.cc:
  Added #ifndef to hide not used variable
storage/connect/connect.cc:
  Added volatile to avoid compiler warning in gcc 4.8.1
storage/connect/filamvct.cpp:
  Added volatile to avoid compiler warning in gcc 4.8.1
storage/maria/ma_checkpoint.c:
  Removed cast to avoid compiler warning
storage/myisam/mi_delete_table.c:
  Added attribute to avoid compiler warning
storage/tokudb/ha_tokudb.cc:
  Use LINT_INIT_STRUCT to avoid compiler warnings
storage/tokudb/hatoku_hton.cc:
  Use LINT_INIT_STRUCT to avoid compiler warnings
storage/tokudb/tokudb_card.h:
  Use LINT_INIT_STRUCT to avoid compiler warnings
storage/tokudb/tokudb_status.h:
  Use LINT_INIT_STRUCT to avoid compiler warnings