RFR: 8343981: Remove usage of security manager from Thread and related classes

[Alan Bateman]

Removes the SecurityManager usage from Thread + friends.

In Thread, the getContextClassLoader method is no longer caller-sensitive method.

JavaLangAccess.newThreadWithAcc is removed and jdk.internal.access is no longer exported to java.naming. The usage of newThreadWithAcc is removed from com.sun.jndi.ldap.VersionHelper. There will be further work on the java.naming module to remove usage of SM, the change here is specific to the usage of ewThreadWithAcc.

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Depends on: https://git.openjdk.org/jdk/pull/21498

Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/22035/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22035&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343981
  Stats: 283 lines in 10 files changed: 0 ins; 228 del; 55 mod
  Patch: https://git.openjdk.org/jdk/pull/22035.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22035/head:pull/22035

PR: https://git.openjdk.org/jdk/pull/22035