Follow-up fix to my change to IsPowerOfTwo: Alignment of one means no alignment, not zero.

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 1232 matching lines @@
 
 ASSEMBLER_TEST_RUN(LargeConstant, test) {
   typedef int64_t (*LargeConstantCode)();
   EXPECT_EQ(kLargeConstant,
             reinterpret_cast<LargeConstantCode>(test->entry())());
 }
 
 
 static int ComputeStackSpaceReservation(int needed, int fixed) {
   static const int kFrameAlignment = OS::ActivationFrameAlignment();
-  return (kFrameAlignment > 0)
+  return (kFrameAlignment > 1)
       ? Utils::RoundUp(needed + fixed, kFrameAlignment) - fixed
       : needed;
 }
 
 
 static int LeafReturn42() {
   return 42;
 }
 
 
@@ skipping 1346 matching lines @@
   EXPECT_EQ(1, res);  // Greater equal.
   res = reinterpret_cast<ConditionalMovesCompareCode>(test->entry())(5, 5);
   EXPECT_EQ(1, res);  // Greater equal.
   res = reinterpret_cast<ConditionalMovesCompareCode>(test->entry())(2, 5);
   EXPECT_EQ(-1, res);  // Less.
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64