RFR: 8260617: Merge ZipFile encoding check with the initial hash calculation [v2]

[Claes Redestad]

> - Merge checkEncoding into the byte[]-based normalizedHash. The latter is only used from ZipFile.initCEN right after the checkEncoding today, so verifying this is equivalent is straightforward.
> - Factor out the logic to calculate hash, check encoding etc into the addEntry method to allow JITs to chew off larger chunks of the logic early on
> 
> Roughly 1.2x speedup on the JarFileMeta microbenchmarks, which include the time required to open the jar file and thus exercising the optimized code.
> 
> Testing: tier1-4

Claes Redestad has updated the pull request incrementally with one additional commit since the last revision:

  Refactor to do most entry validation in one place, out of line from initCEN.

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2306/files
  - new: https://git.openjdk.java.net/jdk/pull/2306/files/ccf4d954..713e03b4

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2306&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2306&range=00-01

  Stats: 71 lines in 2 files changed: 31 ins; 13 del; 27 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2306.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2306/head:pull/2306

PR: https://git.openjdk.java.net/jdk/pull/2306