Fix some ArtMethod related bugs

Added root visiting for runtime methods, not currently required
since the GcRoots in these methods are null.

Added missing GetInterfaceMethodIfProxy in GetMethodLine, fixes
--trace run-tests 005, 044.

Fixed optimizing compiler bug where we used a normal stack location
instead of double on ARM64, this fixes the debuggable tests.

TODO: Fix JDWP tests.

Bug: 19264997

Change-Id: I7c55f69c61d1b45351fd0dc7185ffe5efad82bd3
diff --git a/compiler/optimizing/code_generator.cc b/compiler/optimizing/code_generator.cc
index c106d30..0cd63a6 100644
--- a/compiler/optimizing/code_generator.cc
+++ b/compiler/optimizing/code_generator.cc
@@ -124,13 +124,14 @@
   if (!is_leaf) {
     MarkNotLeaf();
   }
+  const bool is_64_bit = Is64BitInstructionSet(GetInstructionSet());
   InitializeCodeGeneration(GetGraph()->GetNumberOfLocalVRegs()
                              + GetGraph()->GetTemporariesVRegSlots()
                              + 1 /* filler */,
                            0, /* the baseline compiler does not have live registers at slow path */
                            0, /* the baseline compiler does not have live registers at slow path */
                            GetGraph()->GetMaximumNumberOfOutVRegs()
-                             + 1 /* current method */,
+                             + (is_64_bit ? 2 : 1) /* current method */,
                            GetGraph()->GetBlocks());
   CompileInternal(allocator, /* is_baseline */ true);
 }