RFR: 8332245: C2: missing record_for_ign() call in GraphKit::must_be_not_null() [v2]

[Roland Westrelin]

> The `If` node that's created by `GraphKit::must_be_not_null()` is not
> enqueued for igvn when it's created. The test case shows it prevents 2
> identical tests from commoning when the first igvn executes. This is a
> minor issue I noticed whule working on something else.

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

  fixed test @summary

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19233/files
  - new: https://git.openjdk.org/jdk/pull/19233/files/23341ae6..48fb906c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19233&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19233&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/19233.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19233/head:pull/19233

PR: https://git.openjdk.org/jdk/pull/19233