[jdk17u-dev] RFR: 8277417: C1 LIR instruction for load-klass

[Aleksey Shipilev]

Clean backport to resolve the klass-ptr related kludges, match the relevant code to current state of mainline past JDK 18, and make life easier for downstreams like Lilliput JDK 17u.

There are two follow-ups, which are not critical, and which I would backport separately:
  * [JDK-8278141](https://bugs.openjdk.org/browse/JDK-8278141) LIR_OpLoadKlass::_info shadows the field of the same name from LIR_Op
  * [JDK-8277860](https://bugs.openjdk.org/browse/JDK-8277860) PPC: Remove duplicate info != NULL check

Additional testing:
 - [ ] Linux x86_64 fastdebug `tier1 tier2 tier3`
 - [ ] Linux AArch64 fastdebug `tier1 tier2 tier3`

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Commit messages:
 - Backport 99e4bda303f2c71972a125d0ecaf4cf986c8614a

Changes: https://git.openjdk.org/jdk17u-dev/pull/1528/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1528&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8277417
  Stats: 189 lines in 11 files changed: 140 ins; 37 del; 12 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1528.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1528/head:pull/1528

PR: https://git.openjdk.org/jdk17u-dev/pull/1528