RFR: 8310524: C2: record parser-generated LoadN nodes for IGVN [v2]

[Daniel Lundén]

> This changeset fixes an issue where LoadN nodes were not recorded during bytecode parsing for later revisit in IGVN, in some cases resulting in missed optimization opportunities (see, e.g., the included new regression test).
> 
> Changes:
> - Make sure to record newly added LoadN-nodes for IGVN in `GraphKit::make_load`.
> - Add a regression test.
> 
> ### Testing
> - tier1, tier2, tier3, tier4, tier5 (windows-x64, linux-x64, linux-aarch64, macosx-x64, macosx-aarch64)

Daniel Lundén has updated the pull request incrementally with one additional commit since the last revision:

  Address comments

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/16967/files
  - new: https://git.openjdk.org/jdk/pull/16967/files/a238157a..23f80e63

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16967&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16967&range=00-01

  Stats: 4 lines in 2 files changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/16967.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16967/head:pull/16967

PR: https://git.openjdk.org/jdk/pull/16967