RFR: 8331021: Deprecate and obsolete the DontYieldALot flag

[David Holmes]

The `DontYieldALot` flag is an anachronism from very early Java days - see JBS issue for some details. It should be deprecated for removal in JDK 23.

BTW the description of the flag:
> Throw away obvious excess yield calls

has been incorrect for a long time - it throws away all yield calls.

Testing:
 - tiers 1-3 (sanity)

Thanks

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Commit messages:
 - 8331021: Deprecate and obsolete the DontYieldALot flag

Changes: https://git.openjdk.org/jdk/pull/18928/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18928&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331021
  Stats: 3 lines in 3 files changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/18928.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18928/head:pull/18928

PR: https://git.openjdk.org/jdk/pull/18928