Move common static helpers from codegen to the macro-assembler files.

src/ia32/macro-assembler-ia32.h

Index: src/ia32/macro-assembler-ia32.h
===================================================================
--- src/ia32/macro-assembler-ia32.h	(revision 5806)
+++ src/ia32/macro-assembler-ia32.h	(working copy)
@@ -642,6 +642,17 @@
   return Operand(object, index, scale, offset - kHeapObjectTag);
 }
 
+
+static inline Operand ContextOperand(Register context, int index) {
+  return Operand(context, Context::SlotOffset(index));
+}
+
+
+static inline Operand GlobalObjectOperand() {
+  return ContextOperand(esi, Context::GLOBAL_INDEX);
+}
+
+
 // Generates an Operand for saving parameters after PrepareCallApiFunction.
 Operand ApiParameterOperand(int index);