RFR: 8298073: gc/metaspace/CompressedClassSpaceSizeInJmapHeap.java causes test task timeout on macosx

[Chris Plummer]

This fixes two separate CRs:

[JDK-8241293](https://bugs.openjdk.org/browse/JDK-8241293) CompressedClassSpaceSizeInJmapHeap.java time out after 8 minutes
[JDK-8298073](https://bugs.openjdk.org/browse/JDK-8298073) gc/metaspace/CompressedClassSpaceSizeInJmapHeap.java causes test task timeout on macosx

For the first one the test was hitting an 8m timeout, but completing right after that. The test log said PASSED, but jtreg failed it anyway because it noticed the timeout. The fix is to double the default 120s timeout to 240s (which is 16m when the 4x timeoutfactor is applied.

For the second one the issue seemed to be with having the test process spawn a jhsdb process that attached back to the test process. OSX didn't seem to be too happy about this. The fix is to instead create a LingeredApp process to attach to like all the other SA tests do.

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Commit messages:
 - Fix indent.
 - Attach to LingeredApp process rather than to the test process.

Changes: https://git.openjdk.org/jdk/pull/11576/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11576&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8298073
  Stats: 9 lines in 2 files changed: 5 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/11576.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11576/head:pull/11576

PR: https://git.openjdk.org/jdk/pull/11576