RFR: 8258005: JDK build fails with incorrect fixpath script [v2]

[Magnus Ihse Bursie]

> The Leaning Toothpick Syndrome[1] strikes back!
> 
> In the fixpath shell script wrapper, we transform single `` to `\`, to make them correctly escaped. Unfortunately, the bas variable substitution pattern I used were missing a `/`, so it only replaced the first backslash, not all of them.
> 
> Thanks to @vidmik for analysis and fix!
> 
> [1] https://en.wikipedia.org/wiki/Leaning_toothpick_syndrome

Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:

  Also update second instance of WINENV_ROOT backslash rewrite

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1731/files
  - new: https://git.openjdk.java.net/jdk/pull/1731/files/bf0ca7ae..08eec16e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1731&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1731&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1731.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1731/head:pull/1731

PR: https://git.openjdk.java.net/jdk/pull/1731