Revert of improve perf_basic_prof filename reporting (patchset #1 id:1 of...

Revert of improve perf_basic_prof filename reporting (patchset #1 id:1 of https://codereview.chromium.org/1388543002/ )

Reason for revert:
Suspected to cause crbug.com/539892

Original issue's description:
> improve perf_basic_prof filename reporting
>
> The buffer used for appending filenames to the string printed to the
> perf_basic_prof log was unnecessarily too small. Bump it up to be at least
> kUtf8BufferSize.
>
> Truncation of filenames makes it really hard to work with profiles gathered on
> Node.js. Because of the way Node.js works, you can have node module dependencies
> in deeply nested directories. The last thing you want when investigating a
> performance problem is to have script names be truncated.
>
> This patch is a stop-gap. Ideally, I want no truncation of the filename at all
> and use a dynamically growing buffer. That would be a larger change, and I
> wanted to have a quick fix available that can be back-ported to Node.js LTS
> release.
>
> R=yangguo@chromium.org,yurys@chromium.org
> BUG=
>
> Committed: https://crrev.com/03ef3cd004c2fd31ae7e48772f106df67b8c2feb
> Cr-Commit-Position: refs/heads/master@{#31092}

TBR=yangguo@chromium.org,yurys@chromium.org,ofrobots@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1390923004

Cr-Commit-Position: refs/heads/master@{#31137}

src/log.cc

@@ -145,7 +145,7 @@ class CodeEventLogger::NameBuffer {
 
  private:
   static const int kUtf8BufferSize = 512;
-  static const int kUtf16BufferSize = kUtf8BufferSize;
+  static const int kUtf16BufferSize = 128;
 
   int utf8_pos_;
   char utf8_buffer_[kUtf8BufferSize];