RFR: 8278185: Custom JRE cannot find non-ASCII named module inside [v2]

[Toshio Nakamura]

> Could you review this fix?
> 
> Problem:
> Custom JRE generated by jlink cannot find non-ASCII named modules included inside the JRE.
> 
> Cause and fix:
> If module or package name was composed by ASCII then non-ASCII characters, 
> ImageStringsReader:stringFromByteBufferMatches() miscalculated the length of matched string. The first part of ASCII characters was missing. This patch corrected the value.
> 
> Testing:
> tier1 and tier2 on Linux have no regression.
> I wasn't able to create an automate test for this issue. I appreciate any advice.

Toshio Nakamura has updated the pull request incrementally with one additional commit since the last revision:

  Added a testcase

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6693/files
  - new: https://git.openjdk.java.net/jdk/pull/6693/files/6c73d436..9f689aae

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6693&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6693&range=00-01

  Stats: 90 lines in 2 files changed: 90 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6693.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6693/head:pull/6693

PR: https://git.openjdk.java.net/jdk/pull/6693