RFR: 8299155: C2: SubTypeCheckNode::verify() should not produce dependencies / oop pool entries [v2]

[Roland Westrelin]

> This patch simply guarantees a new LoadKlassNode is not created (and
> processed by igvn) unless it's really needed.

Roland Westrelin has updated the pull request incrementally with one additional commit since the last revision:

  review

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12383/files
  - new: https://git.openjdk.org/jdk/pull/12383/files/0ed25bdd..ae8c71d9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12383&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12383&range=00-01

  Stats: 5 lines in 2 files changed: 1 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/12383.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12383/head:pull/12383

PR: https://git.openjdk.org/jdk/pull/12383