[jdk13u-dev] RFR: 8273026: Slow LoginContext.login() on multi threading application

[Larry-N]

Backport the fix  8273026 that added cache of Service Loaders to LoginContext. Fix was not applied cleanly. Tested with tier2.

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Commit messages:
 - Backport c0cda1db4fe74b86faa12136336bdf98c96758d2

Changes: https://git.openjdk.java.net/jdk13u-dev/pull/291/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk13u-dev&pr=291&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273026
  Stats: 53 lines in 3 files changed: 27 ins; 17 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk13u-dev/pull/291.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk13u-dev pull/291/head:pull/291

PR: https://git.openjdk.java.net/jdk13u-dev/pull/291