RFR: 8324585: JVM native memory leak in PCKS11-NSS security provider [v3]

[Daniel Jeliński]

> Please review this patch that fixes a memory leak in P11TlsPrfGenerator, which is triggered during TLS1.2 Finished message generation and verification.
> 
> The patch changes C_SignInit JNI method to free the mechanism data immediately after use. This matches the behavior of other Init methods (like C_EncryptInit). The patch also fixes a similar issue in other signature-related methods.
> 
> The change essentially reverts part of [JDK-8080462](https://bugs.openjdk.org/browse/JDK-8080462).
> 
> All sun/security/pkcs11 tests still pass with NSS ~3.35 and~ 3.91. All tier1-3 tests still pass.
> 
> EDIT:
> Some sun/security/pkcs11 tests fail with NSS 3.64 and older, see [comment](https://github.com/openjdk/jdk/pull/17584#issuecomment-1914665234)

Daniel Jeliński has updated the pull request incrementally with one additional commit since the last revision:

  Improve wording

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/17584/files
  - new: https://git.openjdk.org/jdk/pull/17584/files/87edba10..5a2390d4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17584&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17584&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/17584.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17584/head:pull/17584

PR: https://git.openjdk.org/jdk/pull/17584