[jdk11u-dev] RFR: 8310380: Handle problems in core-related tests on macOS when codesign tool does not work

[Andrew Lu]

I backport this for parity with 11.0.24-oracle.

test/lib-test/jdk/test/lib/TestMutuallyExclusivePlatformPredicates.java
Backport to the origin file.
Other's clean.

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Commit messages:
 - Backport 39c104df44f17c1d65e35becd4272f73e2c6610c

Changes: https://git.openjdk.org/jdk11u-dev/pull/2620/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2620&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310380
  Stats: 56 lines in 4 files changed: 37 ins; 12 del; 7 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2620.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2620/head:pull/2620

PR: https://git.openjdk.org/jdk11u-dev/pull/2620