Ensure inlined static calls perform clinit checks in Optimizing.

Calls to static methods have implicit class initialization
(clinit) checks of the method's declaring class in
Optimizing.  However, when such a static call is inlined,
the implicit clinit check vanishes, possibly leading to an
incorrect behavior.

To ensure that inlining static methods does not change the
behavior of a program, add explicit class initialization
checks (art::HClinitCheck) as well as load class
instructions (art::HLoadClass) as last input of static
calls (art::HInvokeStaticOrDirect) in Optimizing' control
flow graphs, when the declaring class is reachable and not
known to be already initialized.  Then when considering the
inlining of a static method call, proceed only if the method
has no implicit clinit check requirement.

The added explicit clinit checks are already removed by the
art::PrepareForRegisterAllocation visitor.  This CL also
extends this visitor to turn explicit clinit checks from
static invokes into implicit ones after the inlining step,
by removing the added art::HLoadClass nodes mentioned
hereinbefore.

Change-Id: I9ba452b8bd09ae1fdd9a3797ef556e3e7e19c651
diff --git a/compiler/optimizing/intrinsics_x86_64.cc b/compiler/optimizing/intrinsics_x86_64.cc
index d9a1c31..2a9b507 100644
--- a/compiler/optimizing/intrinsics_x86_64.cc
+++ b/compiler/optimizing/intrinsics_x86_64.cc
@@ -105,6 +105,7 @@
 
 static void MoveArguments(HInvoke* invoke, ArenaAllocator* arena, CodeGeneratorX86_64* codegen) {
   if (invoke->InputCount() == 0) {
+    // No argument to move.
     return;
   }