Rename TARGET_OS_* to HOST_OS_*.

runtime/vm/assembler_x64_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/os.h"
 #include "vm/unit_test.h"
@@ skipping 3395 matching lines @@
   EXPECT_EQ(12.0, res);
   res = reinterpret_cast<DoubleToDoubleTruncCode>(test->entry())(-12.3);
   EXPECT_EQ(-12.0, res);
   res = reinterpret_cast<DoubleToDoubleTruncCode>(test->entry())(-12.8);
   EXPECT_EQ(-12.0, res);
 }
 
 
 ASSEMBLER_TEST_GENERATE(DoubleAbs, assembler) {
   EnterTestFrame(assembler);
-#if defined(TARGET_OS_WINDOWS)
+#if defined(HOST_OS_WINDOWS)
   // First argument is code object, second argument is thread. MSVC passes
   // third argument in XMM2.
   __ DoubleAbs(XMM2);
   __ movaps(XMM0, XMM2);
 #else
   // SysV ABI allocates integral and double registers for arguments
   // independently.
   __ DoubleAbs(XMM0);
 #endif
   LeaveTestFrame(assembler);
@@ skipping 153 matching lines @@
   int res = reinterpret_cast<ConditionalMovesNoOverflowCode>(test->entry())(
       0x7fffffffffffffff, 2);
   EXPECT_EQ(1, res);
   res = reinterpret_cast<ConditionalMovesNoOverflowCode>(test->entry())(1, 1);
   EXPECT_EQ(0, res);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64