RFR: 8347397: Cleanup of JDK-8169880

[Peter Levart]

[JDK-8169880](https://bugs.openjdk.org/browse/JDK-8169880) removed a debugging option to disable caching of reflective data in java.lang.Class, which had a consequence that now Class#reflectiveData method guarantees to return a non-null result. Existing callers of that method were left intact and still contain null checks and branches that are never taken after this change. Some new callers were added later and they don't have null checks. I propose a patch to remove these unneeded null checks and never taken branches.

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Commit messages:
 - 8347397: Cleanup of JDK-8169880

Changes: https://git.openjdk.org/jdk/pull/23025/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23025&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347397
  Stats: 57 lines in 1 file changed: 2 ins; 27 del; 28 mod
  Patch: https://git.openjdk.org/jdk/pull/23025.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23025/head:pull/23025

PR: https://git.openjdk.org/jdk/pull/23025