RFR: 8327461: KeyStore getEntry is not thread-safe [v5]

[Hai-May Chao]

> Change was made to engineGetEntry() in PKCS12KeyStore to extract the key and certificate chain from Entry only once. This is because the entry may get updated between engineGetKey() and engineGetCertificateChain() which causes inconsistent result. A new test was added to assess and manipulate PKCS12KeyStore with read and write operations concurrently from multiple threads. Thanks!

Hai-May Chao has updated the pull request incrementally with one additional commit since the last revision:

  remove unneeded checks in engineGetEntry

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18156/files
  - new: https://git.openjdk.org/jdk/pull/18156/files/68c68af2..15220c6b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18156&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18156&range=03-04

  Stats: 9 lines in 1 file changed: 0 ins; 4 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/18156.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18156/head:pull/18156

PR: https://git.openjdk.org/jdk/pull/18156