RFR: 8318826: C2: "Bad graph detected in build_loop_late" with incremental inlining

[Roland Westrelin]

In test case, `test1()`, `inlined1()` returns null which is used as
receiver for the `notInlined()` virtual call. On the fallthrough
projection of the call, the receiver is casted to not null. In the
case of `test1()` the fallthrough should be unreachable:
`CatchNode::Value()` makes that path dead if it is a projection of a
virtual call with a null receiver. When `test1()` is compiled with
incremental inlining, before `inlined1()` is inlined, the receiver of
the virtual call is not known to be null so the fallthrough path is
not killed. When it is inlined, the first input argument to the
virtual call node is updated to be null. So that node is pushed on the
igvn work list. But the `CatchNode` that's not change in the the
process is not. As a result, the fallthrough path of the virtual call
is not killed. The input to the cast node in the fallthrough path is
changed to null which causes that node to become top. That causes the
crash.

IGVN has logic to enqueue nodes that are related to an edge change but
are not directly modified. We would need similar logic to be called
from late inlining code. This change refactors the igvn logic so it
can be called from elsewhere.

`test2()` is similar to `test1()` except the return of the inlined
method `inlined2()` is not set to null. Instead, a replaced node is
recorded from `a` to null (because class `D` is unrelated to `A` so
casting a `A` to `D` successfully only happens for null) and applied
when `inlined2()` is late inlined.

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Commit messages:
 - whitespaces
 - fix & test

Changes: https://git.openjdk.org/jdk/pull/16581/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16581&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318826
  Stats: 341 lines in 5 files changed: 159 ins; 13 del; 169 mod
  Patch: https://git.openjdk.org/jdk/pull/16581.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16581/head:pull/16581

PR: https://git.openjdk.org/jdk/pull/16581