Port inline in-object property stores from ia32 to x64.

src/x64/virtual-frame-x64.cc

Index: src/x64/virtual-frame-x64.cc
===================================================================
--- src/x64/virtual-frame-x64.cc	(revision 5112)
+++ src/x64/virtual-frame-x64.cc	(working copy)
@@ -1150,7 +1150,7 @@
     receiver->Unuse();
   } else {
     // Otherwise, no register is free, and no value is in the correct place.
-    // We have one of the two circular permutations of eax, ecx, edx.
+    // We have one of the two circular permutations of rax, rcx, rdx.
     ASSERT(value->is_register());
     if (value->reg().is(rcx)) {
       __ xchg(rax, rdx);