[jdk11u-dev] RFR: 8272131: PhaseMacroExpand::generate_slow_arraycopy crash when clone null CallProjections.fallthrough_ioproj [v2]

[Hui Shi]

> Please help review this backport for 8272131: C2 crash in PhaseMacroExpand::generate_slow_arraycopy because arraycopy node's _ioproj_fallthrough is NULL.
> 
> Conflicts when backport
> In jdk18:  field name is fallthrough_ioproj , and it is in PhaseMacroExpand's CallProjections class.
> In jdk11:  field name is _ioproj_fallthrough, and it is directly in PhaseMacroExpand class.

Hui Shi has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

   Backport 5350b9901c6cebe5d40bbba9a31d1f26285b1cd6

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Changes:
  - all: https://git.openjdk.java.net/jdk11u-dev/pull/247/files
  - new: https://git.openjdk.java.net/jdk11u-dev/pull/247/files/645b47ad..4afdf7d7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=247&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=247&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/247.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/247/head:pull/247

PR: https://git.openjdk.java.net/jdk11u-dev/pull/247