Re-enable assertion after the problem that caused it to be hit had been fixed.

[AndreyChurbanov]

Summary

The problem of inconsistent pointers to task team in the thread and team structures had been fixed by the commit r249711 (https://reviews.llvm.org/D13353).

Thus the debug assertion can safely be restored.

Tried the test provided in the https://reviews.llvm.org/D11269 which disabled the assertion. That test caused the assertion before r249711, and it work fine now. Not sure if we can add the test for regression testing because it only makes sense on a debug library.

runtime/src/kmp_runtime.cpp

#if OMP_40_ENABLED
     KMP_CHECK_UPDATE(team->t.t_cancel_request, cancel_noreq);
 #endif
 
     // Update the floating point rounding in the team if required.
     propagateFPControl(team);
 
     if ( __kmp_tasking_mode != tskm_immediate_exec ) {
         // Set master's task team to team's task team. Unless this is hot team, it should be NULL.
-#if 0
-        // Patch out an assertion that trips while the runtime seems to operate correctly.
-        // Avoiding the preconditions that cause the assertion to trip has been promised as a forthcoming patch.
         KMP_DEBUG_ASSERT(master_th->th.th_task_team == parent_team->t.t_task_team[master_th->th.th_task_state]);
-#endif
         KA_TRACE( 20, ( "__kmp_fork_call: Master T#%d pushing task_team %p / team %p, new task_team %p / team %p\n",
                       __kmp_gtid_from_thread( master_th ), master_th->th.th_task_team,
                       parent_team, team->t.t_task_team[master_th->th.th_task_state], team ) );
 
         if ( active_level || master_th->th.th_task_team ) {
             // Take a memo of master's task_state
             KMP_DEBUG_ASSERT(master_th->th.th_task_state_memo_stack);
             if (master_th->th.th_task_state_top >= master_th->th.th_task_state_stack_sz) { // increase size