Make ART compile with GCC -O0 again.

Tidy up InstructionSetFeatures so that it has a type hierarchy dependent on
architecture.
Add to instruction_set_test to warn when InstructionSetFeatures don't agree
with ones from system properties, AT_HWCAP and /proc/cpuinfo.
Clean-up class linker entry point logic to not return entry points but to
test whether the passed code is the particular entrypoint. This works around
image trampolines that replicate entrypoints.
Bug: 17993736

Change-Id: I5f4b49e88c3b02a79f9bee04f83395146ed7be23
diff --git a/runtime/reflection.h b/runtime/reflection.h
index 23d8e05..f9a7951 100644
--- a/runtime/reflection.h
+++ b/runtime/reflection.h
@@ -65,7 +65,7 @@
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
 void InvokeWithShadowFrame(Thread* self, ShadowFrame* shadow_frame, uint16_t arg_offset,
-                           MethodHelper& mh, JValue* result)
+                           MethodHelper* mh, JValue* result)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
 jobject InvokeMethod(const ScopedObjectAccessAlreadyRunnable& soa, jobject method, jobject receiver,