RFR: 8284404: Too aggressive sweeping with Loom

[Erik Österlund]

The normal sweeping heuristics trigger sweeping whenever 0.5% of the reserved code cache could have died. Normally that is fine, but with loom such sweeping requires a full GC cycle, as stacks can now be in the Java heap as well. In that context, 0.5% does seem to be a bit too trigger happy. So this patch adjusts that default when using loom to 10x higher.
If you run something like jython which spins up a lot of code, it unsurprisingly triggers a lot less GCs due to code cache pressure.

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Commit messages:
 - 8284404: Too aggressive sweeping with Loom

Changes: https://git.openjdk.java.net/jdk/pull/8673/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8673&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284404
  Stats: 4 lines in 1 file changed: 3 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8673.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8673/head:pull/8673

PR: https://git.openjdk.java.net/jdk/pull/8673