RegExp: Remove use of 16-bit immediates on ia32/x64.

src/ia32/regexp-macro-assembler-ia32.h

Index: src/ia32/regexp-macro-assembler-ia32.h
diff --git a/src/ia32/regexp-macro-assembler-ia32.h b/src/ia32/regexp-macro-assembler-ia32.h
index 823bc03312074023e898fc0bd7b68b3c22aa3299..8b8eeed6ce8c8ffae36f6b407434d2a14bbd6009 100644
--- a/src/ia32/regexp-macro-assembler-ia32.h
+++ b/src/ia32/regexp-macro-assembler-ia32.h
@@ -132,9 +132,8 @@ class RegExpMacroAssemblerIA32: public NativeRegExpMacroAssembler {
   static const int kBackup_edi = kBackup_esi - kPointerSize;
   static const int kBackup_ebx = kBackup_edi - kPointerSize;
   static const int kInputStartMinusOne = kBackup_ebx - kPointerSize;
-  static const int kAtStart = kInputStartMinusOne - kPointerSize;
   // First register address. Following registers are below it on the stack.
-  static const int kRegisterZero = kAtStart - kPointerSize;
+  static const int kRegisterZero = kInputStartMinusOne - kPointerSize;
 
   // Initial size of code buffer.
   static const size_t kRegExpCodeSize = 1024;