Make "typeof this" return object in fast compiler.

src/ia32/fast-codegen-ia32.cc

Index: src/ia32/fast-codegen-ia32.cc
===================================================================
--- src/ia32/fast-codegen-ia32.cc	(revision 3225)
+++ src/ia32/fast-codegen-ia32.cc	(working copy)
@@ -1027,7 +1027,9 @@
       ASSERT_EQ(Expression::kValue, expr->expression()->context());
 
       VariableProxy* proxy = expr->expression()->AsVariableProxy();
-      if (proxy != NULL && proxy->var()->is_global()) {
+      if (proxy != NULL &&
+          !proxy->var()->is_this() &&
+          proxy->var()->is_global()) {
         Comment cmnt(masm_, "Global variable");
         __ push(CodeGenerator::GlobalObject());
         __ mov(ecx, Immediate(proxy->name()));