[jdk11u-dev] RFR: 8303607: SunMSCAPI provider leaks memory and keys

[Mat Carter]

Backport a393f2581740f854518a3ef7caccd6d3c2d8e4a0

Backporting this to 11 as the issue is still relevant; passes tier1 tests and the fix has been verified in 11/windows

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Commit messages:
 - Backport a393f2581740f854518a3ef7caccd6d3c2d8e4a0

Changes: https://git.openjdk.org/jdk11u-dev/pull/2174/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2174&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303607
  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2174.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2174/head:pull/2174

PR: https://git.openjdk.org/jdk11u-dev/pull/2174