RFR: 8344364: Remove unused SecurityManager-related imports from java.lang.instrument.ClassFileTransformer

[Eirik Bjørsnøs]

Please review this trivial cleanup which removes unused imports of `java.security.AccessController` and `java.security.PrivilegedAction` from `java.lang.instrument.ClassFileTransformer`.

History: These imports came with the new transform method introduced by the module system implementation in JDK-8142968 and were left unused when JDK-8159147 instead added a ClassLoader parameter to the new transform method.

Verification: `make images` succeeds.

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Commit messages:
 - Remove unused imports

Changes: https://git.openjdk.org/jdk/pull/22184/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22184&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344364
  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/22184.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22184/head:pull/22184

PR: https://git.openjdk.org/jdk/pull/22184