Remove broken _WIN64 checks.

src/compiler/x64/code-generator-x64.cc

Index: src/compiler/x64/code-generator-x64.cc
diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
index 3c43844c689fa15d6f24be702a800875b942eda6..d23a9e6a074615bf36558bd5fa12ae0f39f2963c 100644
--- a/src/compiler/x64/code-generator-x64.cc
+++ b/src/compiler/x64/code-generator-x64.cc
@@ -16,8 +16,6 @@ namespace v8 {
 namespace internal {
 namespace compiler {
 
-#ifndef _WIN64
-
 #define __ masm()->
 
 
@@ -998,7 +996,6 @@ bool CodeGenerator::IsNopForSmiCodeInlining(Handle<Code> code, int start_pc,
 
 #endif
 
-#endif
-}
-}
-}  // namespace v8::internal::compiler
+}  // namespace internal
+}  // namespace compiler
+}  // namespace v8