[jdk11u-dev] RFR: 8250810: Push missing parts of JDK-8248817

[Reka Kovacs]

This is a refactoring patch with no functional change. It didn't apply cleanly. Differences to the original commit:

In `thread_windows_x86.cpp`:
- Some removed lines were simpler on tip because of [JDK-8248240](https://github.com/openjdk/jdk/commit/a6e794b3e85d28537bf740d9d7e68339707d38e1#diff-d4111d540c34b1e0f4acac1e92877ce458b29d70126ccb113b439261a503ed95).

In `os_windows.cpp`:
- The block around L2461 is no longer present on tip, that and a bit of the next block can be simplified.
- The conditions on L2539 ([JDK-8234372](https://github.com/openjdk/jdk/commit/4e4d1f2b4dad61b4c4590f1d3a956b9ad86ff74c#diff-84938e7dfe64805a850b8a729495117a972a474622fff12bb97ee45cbc2184f2)) and L2549 ([JDK-8213199](https://github.com/openjdk/jdk/commit/7c3f2b06f13e3d28b74193d8acac4478e8c12bdb#diff-84938e7dfe64805a850b8a729495117a972a474622fff12bb97ee45cbc2184f2)) (original line numbers) are different on tip. We actually didn't touch those, they only show up colored in the diff because of the whitespace changes.
- The surrounding code is different around L2586 because of [JDK-8191278](https://github.com/openjdk/jdk/commit/aedbb7580334cb9131f547845f9b7aa3916ddf4b#diff-84938e7dfe64805a850b8a729495117a972a474622fff12bb97ee45cbc2184f2), but the changes are the same.

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Commit messages:
 - Backport a4eaf9536c272862b5ec856bf263679be09bddc9

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/274/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=274&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8250810
  Stats: 76 lines in 2 files changed: 6 ins; 33 del; 37 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/274.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/274/head:pull/274

PR: https://git.openjdk.java.net/jdk11u-dev/pull/274