RFR: 8255883: Avoid duplicated GeneratedMethodAccessor when reflect method invoked from different threads

[Hui Shi]

…ructorAccessorImpl object

duplicate with https://github.com/openjdk/jdk/pull/1070, try trigger test with new PR

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Commit messages:
 - 8255883: Avoid multiple GeneratedAccessor for same NativeMethod/ConstructorAccessorImpl object

Changes: https://git.openjdk.java.net/jdk/pull/1213/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1213&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255883
  Stats: 46 lines in 2 files changed: 28 ins; 0 del; 18 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1213.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1213/head:pull/1213

PR: https://git.openjdk.java.net/jdk/pull/1213