RFR: JDK-8262472: Buffer overflow in UNICODE::as_utf8 for zero length output buffer [v2]

[Thomas Stuefe]

> This one is trivial and probably inconsequential, but lets fix it anyway.
> 
> There is a buffer overflow in both variants of UNICODE::as_utf8, where in case of truncation due to a zero length output buffer the terminating zero still gets written.
> 
> Added fix + gtest. Ran gtest.

Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:

  assert instead

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2753/files
  - new: https://git.openjdk.java.net/jdk/pull/2753/files/598212e0..ebc602cd

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2753&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2753&range=00-01

  Stats: 8 lines in 2 files changed: 0 ins; 4 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2753.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2753/head:pull/2753

PR: https://git.openjdk.java.net/jdk/pull/2753