Check-cast, instance-of, misc fixes

Support for check-cast and instanceof (largely untested).  Added a bunch of
helper stubs, a debugging option to show the method name if we try to branch
to an uncompiled method, new tests and a missing call to reset the compiler's
arena storage.

Change-Id: I933ad1fbdbca110f92c9201cae2353bf4862a8ac
diff --git a/src/compiler/Frontend.cc b/src/compiler/Frontend.cc
index 8488606..2abefe10 100644
--- a/src/compiler/Frontend.cc
+++ b/src/compiler/Frontend.cc
@@ -671,6 +671,7 @@
 bool oatCompileMethod(Method* method, art::InstructionSet insnSet)
 {
     LOG(INFO) << "Compiling " << PrettyMethod(method) << "...";
+    oatArenaReset();
 
     CompilationUnit cUnit;
     art::ClassLinker* class_linker = art::Runtime::Current()->GetClassLinker();