RFR: 8329340: Remove unused libawt code

[Daniel Jeliński]

Please review this PR that removes unused functions, variables, and WM_AWT window messages.

The unused code was detected by automated analysis (MSVC compiler and linker, CodeQL analyzer). I manually verified every symbol before removing. Mach5 client libs testing clean.

Some WM_AWT messages have different IDs after this change. The IDs have changed a few times before, so I think this shouldn't be a problem.

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Commit messages:
 - Remove unused variables
 - Remove OLEHolder
 - Remove EnvHolder
 - Remove jFontToWFontA
 - Remove awtIEClazz
 - Remove DumpRegion
 - Remove IsSupportedLevel
 - Remove GDIWinSD_SimpleClip
 - Remove GDIWinSD_CheckMonitorArea
 - Remove SetHeapCheck
 - ... and 10 more: https://git.openjdk.org/jdk/compare/7ac2f914...cbf7bbd3

Changes: https://git.openjdk.org/jdk/pull/18553/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18553&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8329340
  Stats: 711 lines in 23 files changed: 0 ins; 709 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/18553.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18553/head:pull/18553

PR: https://git.openjdk.org/jdk/pull/18553