[jdk11u-dev] RFR: 8268974: GetJREPath() JLI function fails to locate libjava.so if not standard Java launcher is used

[Sergey Nazarkin]

I'd like to backport this changes as it fixes some custom launchers issue.  The backport is not clean:
1. [8234821](https://bugs.openjdk.org/browse/JDK-8234821) was not backported to jdk11, so *java_md_common.c* need manual adjusting.
2. The test can't be started as it depends on whole jpackage test [pack](https://bugs.openjdk.org/browse/JDK-8268974). So I've removed it.

The functionality was tested with simple 
1.     cd ~/tools/bin
2.     cp -r ~/jdk .
3.     cp jdk/bin/java jdk/lib
5.     jdk/lib/java -version

Without the patch it show the error
       Error: could not find libjava.so
       Error: Could not find Java SE Runtime Environment.

jdk_tier2 is OK as well

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

Commit messages:
 - Remove test
 - fixup! Backport 984003d5c969443abae2d889e92cba30da26e55f
 - Backport 984003d5c969443abae2d889e92cba30da26e55f

Changes: https://git.openjdk.org/jdk11u-dev/pull/2578/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2578&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8268974
  Stats: 15 lines in 1 file changed: 8 ins; 1 del; 6 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2578.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2578/head:pull/2578

PR: https://git.openjdk.org/jdk11u-dev/pull/2578