RFR: 8291736: find_method_handle_intrinsic leaks Method* [v4]

[Coleen Phillimore]

> As part of the SymbolPropertyTable conversion, we noticed that threads could race to add the Method entry to the table, and the loser wasn't deleted.  This change locks the InvokeMethodTable_lock through the Method creation so that it's not leaked.  See bug for details, but this was performance tested with our general suite of performance tests to show no significant differences.
> Also tested with tier1-3, and previously 4-7 with SymbolPropertyTable conversion patch.

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Add comment

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9983/files
  - new: https://git.openjdk.org/jdk/pull/9983/files/f8e85da2..d0ead64c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9983&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9983&range=02-03

  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/9983.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9983/head:pull/9983

PR: https://git.openjdk.org/jdk/pull/9983