RFR: 8293170: Improve encoding of the debuginfo nmethod section

[Boris Ulasevich]

The nmethod "scopes data" section is 10% of the size of nmethod. Now the data is compressed using the Pack200 algorithm, which is good for encoding small integers (LineNumberTable, etc). Using the fact that half of the data in the partition contains zeros, I reduce its size by another 30%.
 
Testing: jtreg hotspot&jdk, Renaissance benchmarks

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Commit messages:
 - optimize the encoding
 - fix
 - 8293170: Improve encoding of the debuginfo nmethod section

Changes: https://git.openjdk.org/jdk/pull/10025/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10025&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293170
  Stats: 226 lines in 8 files changed: 199 ins; 6 del; 21 mod
  Patch: https://git.openjdk.org/jdk/pull/10025.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10025/head:pull/10025

PR: https://git.openjdk.org/jdk/pull/10025