CodeTracer should open file in binary mode to avoid line endings normalization.

Review URL: https://codereview.chromium.org/924943006

Cr-Commit-Position: refs/heads/master@{#26678}

src/isolate.h

@@ -1561,7 +1561,7 @@ class CodeTracer FINAL : public Malloced {
     }
 
     if (file_ == NULL) {
-      file_ = base::OS::FOpen(filename_.start(), "a");
+      file_ = base::OS::FOpen(filename_.start(), "ab");
     }
 
     scope_depth_++;