RFR: 8340493: Fix some Asserts failure messages

[Weijun Wang]

`Asserts.assertNotEquals` shows "expected 12345 to not equal 12345" which sounds redundant, just say "expected not equals but was 12345".

`Asserts.assertEqualsByteArray` uses the words "expected... to equal...". Modify it to follow the `assertEquals` style ""expected... but was...".

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

Commit messages:
 - the fix

Changes: https://git.openjdk.org/jdk/pull/21101/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21101&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8340493
  Stats: 5 lines in 1 file changed: 0 ins; 2 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/21101.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21101/head:pull/21101

PR: https://git.openjdk.org/jdk/pull/21101