Add suppresion file for helgrind for disjointPool test

Helgrind is complaining:
"pthread_mutex_lock with a pthread_rwlock_t* argument"

The call to pthread_mutex_lock is coming from c++ standard lib so
the only thing we can do is to suppress it.

Author: igchor

test/supp/helgrind-umf_test-disjointPool.supp

@@ -0,0 +1,13 @@
+{
+   Incompatibility with c++ std lib ("pthread_mutex_lock with a pthread_rwlock_t* argument")
+   Helgrind:Misc
+   fun:mutex_lock_WRK
+   fun:pthread_mutex_lock
+}
+
+{
+   Incompatibility with c++ std lib ("pthread_mutex_unlock with a pthread_rwlock_t* argument")
+   Helgrind:Misc
+   fun:mutex_unlock_WRK
+   fun:pthread_mutex_unlock
+}

test/test_valgrind.sh

@@ -84,7 +84,7 @@ for test in $(ls -1 umf_test-*); do
 	FILTER=""
 	case $test in
 	umf_test-disjointPool) # TODO: temporarily skip failing disjointPool tests - fix it
-		FILTER='--gtest_filter="-*pow2AlignedAlloc:*multiThreadedpow2AlignedAlloc"'
+		FILTER='--gtest_filter="-*pow2AlignedAlloc"'
 		;;
 	umf_test-memspace_host_all)
 		FILTER='--gtest_filter="-*allocsSpreadAcrossAllNumaNodes"'