Fix sporadic segfaults in tasking tests

[AndreyChurbanov]

Summary

Wrong size calculated for memory copying during re-sizing of array of threads data.

Patch by Terry Wilmarth.

[omalyshe]

LGTM.

runtime/src/kmp_tasking.cpp

if (maxthreads < nthreads) {
         // Reallocate threads_data to have more elements than current array
         // Cannot use __kmp_thread_realloc() because threads not around for
         // kmp_reap_task_team( ).  Note all new array entries are initialized
         // to zero by __kmp_allocate().
         new_data = (kmp_thread_data_t *)__kmp_allocate(
             nthreads * sizeof(kmp_thread_data_t));
         // copy old data to new data
         KMP_MEMCPY_S((void *)new_data, nthreads * sizeof(kmp_thread_data_t),
-                     (void *)old_data, maxthreads * sizeof(kmp_taskdata_t *));
+                     (void *)old_data, maxthreads * sizeof(kmp_thread_data_t));
 
 #ifdef BUILD_TIED_TASK_STACK
         // GEH: Figure out if this is the right thing to do
         for (i = maxthreads; i < nthreads; i++) {
           kmp_thread_data_t *thread_data = &(*threads_data_p)[i];
           __kmp_init_task_stack(__kmp_gtid_from_thread(thread), thread_data);
         }
 #endif // BUILD_TIED_TASK_STACK