RFR: 8287895: Some langtools tests fail on msys2 [v2]

[Magnus Ihse Bursie]

> A bunch of langtools tests, which all rely on `test/langtools/tools/javac/Paths/Util.sh`, fails when run on Windows with msys2, since this environment is not properly detected.

Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:

  Update copyright year

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/9056/files
  - new: https://git.openjdk.java.net/jdk/pull/9056/files/5d19cbf6..2633f9d1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=9056&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=9056&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/9056.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/9056/head:pull/9056

PR: https://git.openjdk.java.net/jdk/pull/9056