RFR: 8299275: Add some ClassLoaderData verification code [v3]

[Coleen Phillimore]

> I added some verification code to try to help track down JDK-8296915 (https://bugs.openjdk.org/browse/JDK-8296915).
> Ran Test: runtime/SelectionResolution/InvokeInterfaceSuccessTest.java 100x with -XX:+VerifyBefore/AfterGC.
> Tested with tier1-4.

Coleen Phillimore has updated the pull request incrementally with two additional commits since the last revision:

 - Fix some english.
 - Walk other non-mirror oops in CLD::_handles area and add a comment why not mirrors.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/11856/files
  - new: https://git.openjdk.org/jdk/pull/11856/files/4775cbc9..5b425763

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11856&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11856&range=01-02

  Stats: 5 lines in 1 file changed: 1 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/11856.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11856/head:pull/11856

PR: https://git.openjdk.org/jdk/pull/11856