RFR: 8167015: compiler/codecache/jmx/PoolsIndependenceTest.java timeout

[Evgeny Nikitin]

Fixed some issues in the test:

1. Replaced obvious mistake with event duration equal to `beginTimestamp - lastEventTimestamp` (giving negative value)
2. Using timeouts to address the problem with notification not being sent due to code cache usage never hitting the limit. Possible explanations:
    Code cache was cleaned just after setting the limit;
    CodeCacheUtils silently failed the blob allocation, causing the notification to never get fired
3. Provided some additional info in both the test log, and failure messages.

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Commit messages:
 - Un-problemlist the PoolsIndependenceTest
 - 8167015: compiler/codecache/jmx/PoolsIndependenceTest.java timeout

Changes: https://git.openjdk.java.net/jdk/pull/3033/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3033&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8167015
  Stats: 35 lines in 2 files changed: 29 ins; 1 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3033.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3033/head:pull/3033

PR: https://git.openjdk.java.net/jdk/pull/3033