RFR: do not generate null checks for record patterns [v2]

[Vicente Romero]

> do not generate null checks for record patterns

Vicente Romero has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'bworld' into do.not.generate.null.checks.for.record.patterns
 - do not generate null checks for record patterns

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Changes:
  - all: https://git.openjdk.org/valhalla/pull/1884/files
  - new: https://git.openjdk.org/valhalla/pull/1884/files/38845f27..6cd6ebf8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1884&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1884&range=00-01

  Stats: 890 lines in 37 files changed: 347 ins; 356 del; 187 mod
  Patch: https://git.openjdk.org/valhalla/pull/1884.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1884/head:pull/1884

PR: https://git.openjdk.org/valhalla/pull/1884