Improve error message in RunRootClinits

Useful for diagnosing current instrumentation and golem issues.

Bug: 157459881
Test: Observe the new message
Change-Id: I5fa68aba5b4e2319504ed3b3ec70d48f1a87eec5
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index fa698f1..bbf59bc 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -1133,8 +1133,10 @@
     if (!c->IsArrayClass() && !c->IsPrimitive()) {
       StackHandleScope<1> hs(self);
       Handle<mirror::Class> h_class(hs.NewHandle(c));
-      EnsureInitialized(self, h_class, true, true);
-      self->AssertNoPendingException();
+      if (!EnsureInitialized(self, h_class, true, true)) {
+        LOG(FATAL) << "Exception when initializing " << h_class->PrettyClass()
+            << ": " << self->GetException()->Dump();
+      }
     } else {
       DCHECK(c->IsInitialized());
     }