Reland "Fixed a couple of failing DCHECK(has_pending_exception())."

src/runtime/runtime-debug.cc

Index: src/runtime/runtime-debug.cc
diff --git a/src/runtime/runtime-debug.cc b/src/runtime/runtime-debug.cc
index d071cbf7f9ddfb721c417899d422ecf83c6e2520..91b6ee5db2d1e78742424458a5c9ab681f2b723a 100644
--- a/src/runtime/runtime-debug.cc
+++ b/src/runtime/runtime-debug.cc
@@ -2748,6 +2748,10 @@ RUNTIME_FUNCTION(Runtime_DebugGetLoadedScripts) {
   Handle<FixedArray> instances;
   {
     DebugScope debug_scope(isolate->debug());
+    if (debug_scope.failed()) {
+      DCHECK(isolate->has_pending_exception());
+      return isolate->heap()->exception();
+    }
     // Fill the script objects.
     instances = isolate->debug()->GetLoadedScripts();
   }