RFR: JDK-8286191: misc tests fail due to JDK-8286191

[Matthias Baesken]

The isMusl method had to be handled in test/lib-test/jdk/test/lib/TestMutuallyExclusivePlatformPredicates.java .
Additionally, the vm.musl predicate seem not to be available in the langtools tests.

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Commit messages:
 - remove from ProblemList
 - Merge remote-tracking branch 'origin/master' into JDK-8286191
 - JDK-8286191

Changes: https://git.openjdk.java.net/jdk/pull/8556/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8556&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8286191
  Stats: 4 lines in 3 files changed: 0 ins; 3 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8556.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8556/head:pull/8556

PR: https://git.openjdk.java.net/jdk/pull/8556