Fix EhFrameTest.Alignment unit test on ARM.

R=machenbach@chromium.org
BUG=v8:4899
LOG=N

Review-Url: https://codereview.chromium.org/2153443002
Cr-Commit-Position: refs/heads/master@{#37772}

test/unittests/eh-frame-writer-unittest.cc

@@ -42,7 +42,7 @@ TEST_F(EhFrameWriterTest, Alignment) {
   ASSERT_EQ(0, EhFrameConstants::kEhFrameTerminatorSize % 4);
   EXPECT_EQ(0, (iterator.GetBufferSize() - EhFrameConstants::kEhFrameHdrSize -
                 EhFrameConstants::kEhFrameTerminatorSize) %
-                   8);
+                   kPointerSize);
 }
 
 TEST_F(EhFrameWriterTest, FDEHeader) {