AArch64: Fix cmp-long and method with long arguments.

1. Fix cmp-long.
2. Use single register to pass long argument.
3. Flush StackReference<ArtMethod> on arm64 the same as in common code.
3. Fix the mismatch in calculate reg offset.

Change-Id: Ie2723260fb143512e4da6ee88d4f3aded80d3d5e
diff --git a/compiler/dex/quick/gen_invoke.cc b/compiler/dex/quick/gen_invoke.cc
index 1817fd3..842533b 100644
--- a/compiler/dex/quick/gen_invoke.cc
+++ b/compiler/dex/quick/gen_invoke.cc
@@ -434,7 +434,7 @@
  */
 void Mir2Lir::FlushIns(RegLocation* ArgLocs, RegLocation rl_method) {
   /*
-   * Dummy up a RegLocation for the incoming Method*
+   * Dummy up a RegLocation for the incoming StackReference<mirror::ArtMethod>
    * It will attempt to keep kArg0 live (or copy it to home location
    * if promoted).
    */