RFR: 8364226: Better ECDSASignature Memory Management [v2]

[Kevin Driver]

> Enhance the memory management/cleanup for `ECDSASignature`.

Kevin Driver has updated the pull request incrementally with one additional commit since the last revision:

  simplify detection of when to zero

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26516/files
  - new: https://git.openjdk.org/jdk/pull/26516/files/7909b0e4..2cfaefcd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26516&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26516&range=00-01

  Stats: 9 lines in 1 file changed: 0 ins; 5 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/26516.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26516/head:pull/26516

PR: https://git.openjdk.org/jdk/pull/26516