RFR: 8293806: JDK_JAVA_OPTIONS picked up twice if launcher re-executes itself

[Dmitry Samersoff]

If the user has set LD_LIBRARY_PATH to use a particular libjvm.so, options from the JDK_JAVA_OPTIONS environment variable are picked up twice.

If an option cannot be accepted twice (e.g., -agentlib), the application fails to start.

The same happens on operating systems that doesn't support $RPATH/$ORIGIN and always have to set LD_LIBRARY_PATH and re-exec the launcher.

This fix takes the approach to re-launch as early as possible, as discussed here:

https://github.com/openjdk/jdk/pull/10430

This PR consists of three commits:
1. Cleanup of java_md.c
2. The implementation of early re-launch
3. Performance optimization

@AlanBateman, @dholmes-ora Alan, David - any comments are appreciated.

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Commit messages:
 - 8293806: performance optimization
 - 8293806: core functionality
 - 8293806: cleanup of java_md.c

Changes: https://git.openjdk.org/jdk/pull/11538/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11538&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293806
  Stats: 216 lines in 6 files changed: 113 ins; 70 del; 33 mod
  Patch: https://git.openjdk.org/jdk/pull/11538.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11538/head:pull/11538

PR: https://git.openjdk.org/jdk/pull/11538