RFR: 8329704: Implement framework for proper handling of JDK_LIBS [v6]

[Magnus Ihse Bursie]

> This is the pinnacle of the recent stream of refactorings in the build system. This patch introduces a more abstract concept of "JDK_LIBS", where only the library name (e.g. "java" or "java.desktop:jawt") is specified, and the build system turns this into suitable linker flags: `-ljawt -L<correct path>` or `jawt.lib -libpath:<correct path>`, depending on linker. It will also automatically create proper dependencies.

Magnus Ihse Bursie has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 14 additional commits since the last revision:

 - Merge branch 'master' into jdk-libs-framework
 - Update parsing to new syntax, and add missing "lib" prefix for gtest.
 - Use new syntax
 - Clarify libjvm virtual library
 - Fix indentation
 - Remove misplaced line
 - Clarify how JDK_LIBS affect other arguments
 - Set JVM_VARIANT_PATH before use
 - Explain ResolveLibPath result
   
   Co-authored-by: Erik Joelsson <37597443+erikj79 at users.noreply.github.com>
 - Fix libfallbackLinker
 - ... and 4 more: https://git.openjdk.org/jdk/compare/20f7321c...b8bedc8b

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18649/files
  - new: https://git.openjdk.org/jdk/pull/18649/files/3ce7793c..b8bedc8b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18649&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18649&range=04-05

  Stats: 12308 lines in 380 files changed: 6978 ins; 3460 del; 1870 mod
  Patch: https://git.openjdk.org/jdk/pull/18649.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18649/head:pull/18649

PR: https://git.openjdk.org/jdk/pull/18649