8013214: BigApps fails due to 'fatal error: Illegal threadstate encountered: 6'

Summary: Grab and drop SR_lock to get the thread to honor the safepoint protocol
Reviewed-by: dcubed, coleenp

src/share/vm/services/memBaseline.cpp

@@ -156,7 +156,8 @@ bool MemBaseline::baseline_malloc_summary(const MemPointerArray* malloc_records)
 // for the safepoint
 void MemBaseline::check_safepoint(JavaThread* thr) {
   if (SafepointSynchronize::is_synchronizing()) {
-    SafepointSynchronize::block(thr);
+    // grab and drop the SR_lock to honor the safepoint protocol
+    MutexLocker ml(thr->SR_lock());
   }
 }