[jdk11u-dev] RFR: 8290529: C2: assert(BoolTest(btest).is_canonical()) failure

[Goetz Lindenmaier]

I backport this for parity with 11.0.18-oracle.

I had to skip parts of the tests because the C2 testing framwork ir_framework is not available in 11.

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Commit messages:
 - Backport 77e21c57ce00463db4cc3d87f93729cbfe2c96b4

Changes: https://git.openjdk.org/jdk11u-dev/pull/1457/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1457&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290529
  Stats: 50 lines in 2 files changed: 47 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1457.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1457/head:pull/1457

PR: https://git.openjdk.org/jdk11u-dev/pull/1457