RFR: 8351493: Revert build changes that are no longer needed

[Magnus Ihse Bursie]

I compared the hermetic-java-runtime branch with mainline, and noticed some old build changes lingering, that are no longer needed. Furthermore, I checked a handful of other files and noticed a few spurious changes that just make the branch differ from mainline for no good reason. I also reverted those.

With this patch, the difference between hermetic-java-runtime and mainline gets even more minimal.

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Commit messages:
 - Revert build changes that are no longer needed. Also revert some non-relevant differences with mainline.

Changes: https://git.openjdk.org/leyden/pull/47/files
  Webrev: https://webrevs.openjdk.org/?repo=leyden&pr=47&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8351493
  Stats: 27 lines in 8 files changed: 0 ins; 26 del; 1 mod
  Patch: https://git.openjdk.org/leyden/pull/47.diff
  Fetch: git fetch https://git.openjdk.org/leyden.git pull/47/head:pull/47

PR: https://git.openjdk.org/leyden/pull/47