CW on Master: Propagate or throw exception when no class found happens in interpreter.

The old behavior is a check fail which causes zygote process crash.

This is particular a problem for CW in which webview is not used, and
this stops CW system start.

Change-Id: I45f26d6e5d328de7f156793f9044f6bf3f878a1a
diff --git a/runtime/interpreter/interpreter_common.cc b/runtime/interpreter/interpreter_common.cc
index c7fb884..9f04b90 100644
--- a/runtime/interpreter/interpreter_common.cc
+++ b/runtime/interpreter/interpreter_common.cc
@@ -772,8 +772,13 @@
     // shadow_frame.GetMethod()->GetDeclaringClass()->GetClassLoader();
     Class* found = Runtime::Current()->GetClassLinker()->FindClass(
         self, descriptor.c_str(), NullHandle<mirror::ClassLoader>());
-    CHECK(found != NULL) << "Class.forName failed in un-started runtime for class: "
-        << PrettyDescriptor(descriptor);
+    if (found == NULL) {
+      if (!self->IsExceptionPending()) {
+        AbortTransaction(self, "Class.forName failed in un-started runtime for class: %s",
+                         PrettyDescriptor(descriptor).c_str());
+      }
+      return;
+    }
     result->SetL(found);
   } else if (name == "java.lang.Class java.lang.Void.lookupType()") {
     result->SetL(Runtime::Current()->GetClassLinker()->FindPrimitiveClass('V'));