RFR: 8293499: Provide jmod compression level option [v2]

[Aleksey Shipilev]

> I have been looking into `make clean-images images` performance, and realized jmod keeps compressing files with default compression level. Tuning that toward lighter compression levels improves build performance considerably, without a heavy loss in *.jmod sizes. 
> 
> This PR allows JMOD to select the compression level. Follow-ups would use this in the build system, see #10214.
> 
> This change nominally requires CSR, but I would like to gauge the reaction to this patch first, before submitting a formal CSR. The interesting asymmetry against `jlink` is: `jlink` provides `--compress` option that only takes `2` for "ZIP compression". (Separately, we could argue if it would be beneficial to add `--compression-level` to `jlink` as well, so to select the compression level there too.)

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Only accept --compression-level when creating the archive
 - Merge branch 'master' into JDK-8293499-jmod-compression-level
 - Fix

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Changes:
  - all: https://git.openjdk.org/jdk/pull/10213/files
  - new: https://git.openjdk.org/jdk/pull/10213/files/8f1dc761..c44ecf01

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10213&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10213&range=00-01

  Stats: 45099 lines in 404 files changed: 23431 ins; 20112 del; 1556 mod
  Patch: https://git.openjdk.org/jdk/pull/10213.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10213/head:pull/10213

PR: https://git.openjdk.org/jdk/pull/10213