RFR: 8293170: Improve encoding of the debuginfo nmethod section [v14]

[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

Boris Ulasevich has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 17 commits:

 - minor api refactoring: start_scope and roll_back instead of position and set_position
 - buffer() returns const array
 - cleanup, rename
 - warning fix
 - add test for buffer grow
 - adding jtreg test for CompressedSparseDataReadStream impl
 - align java impl to cpp impl
 - rewrite the SparseDataWriteStream not to use _curr_byte
 - introduce and call flush() excplicitly, add the gtest
 - minor renaming. adding encoding examples table
 - ... and 7 more: https://git.openjdk.org/jdk/compare/b035056d...1d6cdb73

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Changes: https://git.openjdk.org/jdk/pull/10025/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10025&range=13
  Stats: 547 lines in 12 files changed: 519 ins; 0 del; 28 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