MDEV-6247 post-fix: Re-enable some debug assertions

These assertions were disabled in MariaDB 10.1.1 in commit df4dd59 with a bogus comment referring to the function wsrep_fake_trx_id() that was introduced in the very same commit.

Author: dr-m

storage/innobase/include/trx0sys.ic

@@ -445,10 +445,7 @@ trx_id_t
 trx_sys_get_new_trx_id(void)
 /*========================*/
 {
-#ifndef WITH_WSREP
-/* wsrep_fake_trx_id violates this assert */
 ut_ad(mutex_own(&trx_sys->mutex));
-#endif /* WITH_WSREP */
 
 /* VERY important: after the database is started, max_trx_id value is
 divisible by TRX_SYS_TRX_ID_WRITE_MARGIN, and the following if

storage/innobase/trx/trx0sys.cc

@@ -180,12 +180,7 @@ trx_sys_flush_max_trx_id(void)
 mtr_tmtr;
 trx_sysf_t*	sys_header;
 
-#ifndef WITH_WSREP
- /* wsrep_fake_trx_id violates this assert
- * Copied from trx_sys_get_new_trx_id
- */
 ut_ad(mutex_own(&trx_sys->mutex));
-#endif /* WITH_WSREP */
 
 if (!srv_read_only_mode) {
 mtr_start(&mtr);

storage/xtradb/include/trx0sys.ic

@@ -474,10 +474,7 @@ trx_id_t
 trx_sys_get_new_trx_id(void)
 /*========================*/
 {
-#ifndef WITH_WSREP
-/* wsrep_fake_trx_id violates this assert */
 ut_ad(mutex_own(&trx_sys->mutex));
-#endif /* WITH_WSREP */
 
 /* VERY important: after the database is started, max_trx_id value is
 divisible by TRX_SYS_TRX_ID_WRITE_MARGIN, and the following if

storage/xtradb/trx/trx0sys.cc

@@ -184,12 +184,7 @@ trx_sys_flush_max_trx_id(void)
 mtr_tmtr;
 trx_sysf_t*	sys_header;
 
-#ifndef WITH_WSREP
- /* wsrep_fake_trx_id violates this assert
- * Copied from trx_sys_get_new_trx_id
- */
 ut_ad(mutex_own(&trx_sys->mutex));
-#endif /* WITH_WSREP */
 
 if (!srv_read_only_mode) {
 mtr_start(&mtr);