Add support for nested method verifiers

Can occur in the following scenario:
MethodVerifier::Verify -> MethodVerifier::GetStaticField ->
ResolveFieldJLS ->  ThrowNoSuchFieldError -> EnsureInitialized ->
VerifyClass

Also fixed another case where we can be requested to dump for ANR
while we are suspended in one of the AllowSuspension points.

Bug: 20140397

Change-Id: Ib17f6b98954caa5d1ea1c1dcde66091cc6d11c25
diff --git a/runtime/verifier/method_verifier.cc b/runtime/verifier/method_verifier.cc
index d0f8468..9fc2658 100644
--- a/runtime/verifier/method_verifier.cc
+++ b/runtime/verifier/method_verifier.cc
@@ -395,12 +395,12 @@
       has_virtual_or_interface_invokes_(false),
       verify_to_dump_(verify_to_dump),
       allow_thread_suspension_(allow_thread_suspension) {
-  self->SetVerifier(this);
+  self->PushVerifier(this);
   DCHECK(class_def != nullptr);
 }
 
 MethodVerifier::~MethodVerifier() {
-  Thread::Current()->ClearVerifier(this);
+  Thread::Current()->PopVerifier(this);
   STLDeleteElements(&failure_messages_);
 }