RFR: 8260617: Merge ZipFile encoding check with the initial hash calculation [v3]

[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:

  Clarify comments, put normal path branch first in UTF8 checkedHash

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2306/files
  - new: https://git.openjdk.java.net/jdk/pull/2306/files/713e03b4..bb1659e3

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2306&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2306&range=01-02

  Stats: 12 lines in 1 file changed: 4 ins; 5 del; 3 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