RFR: 8349559: ci doesn't need to store protection domain

[Coleen Phillimore]

The compiler interface has a protection_domain field that it uses for matching in its version of not-yet loaded classes, but class loading only uses (class, class-loader) as an identifier for loaded classes so the compiler interface should do the same.  From the code, I can't see any situation where the protection_domain wouldn't match if name and class loader match.
Tested with tier1-7.

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Commit messages:
 - 8349559: ci doesn't need to store protection domain

Changes: https://git.openjdk.org/jdk/pull/23496/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23496&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349559
  Stats: 41 lines in 5 files changed: 0 ins; 33 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/23496.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23496/head:pull/23496

PR: https://git.openjdk.org/jdk/pull/23496