[jdk11u-dev] RFR: 8282730: LdapLoginModule throw NPE from logout method after login failure

[Goetz Lindenmaier]

I backport this for parity with 11.0.18-oracle.

I had to resolve 6 Copyrights. Will mark as clean.

Copyrights in these files:
src/java.base/share/classes/javax/security/auth/login/LoginContext.java
src/java.management/share/classes/com/sun/jmx/remote/security/FileLoginModule.java
src/jdk.security.auth/share/classes/com/sun/security/auth/module/JndiLoginModule.java
src/jdk.security.auth/share/classes/com/sun/security/auth/module/LdapLoginModule.java
src/jdk.security.auth/share/classes/com/sun/security/auth/module/NTLoginModule.java
src/jdk.security.auth/share/classes/com/sun/security/auth/module/UnixLoginModule.java

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Commit messages:
 - Backport 554f44ecb1134acff3eaf02e2e1c0e01158ab7e5

Changes: https://git.openjdk.org/jdk11u-dev/pull/1491/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1491&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8282730
  Stats: 223 lines in 11 files changed: 151 ins; 2 del; 70 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1491.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1491/head:pull/1491

PR: https://git.openjdk.org/jdk11u-dev/pull/1491