RFR: 8341778: Some javac tests ignore the result of JavacTask::call

[Vicente Romero]

Several tests are ignoring the result of invoking com.sun.source.util.JavacTask::call which returns a `Boolean`. This implies that tests could seem to pass when in reality they are silently failing. This PR is fixing this issue by checking, in all applicable cases the result of the invocation.

TIA

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Commit messages:
 - 8341778: Some javac tests ignore the result of task.call()

Changes: https://git.openjdk.org/jdk/pull/25645/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25645&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8341778
  Stats: 136 lines in 33 files changed: 88 ins; 1 del; 47 mod
  Patch: https://git.openjdk.org/jdk/pull/25645.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25645/head:pull/25645

PR: https://git.openjdk.org/jdk/pull/25645