RFR: Upstream merge to jdk-12+19

[Roman Kennke]

Lots of good stuff from upstream:

- 8212610: Fix handling of memory in PhaseIdealLoop::clone_loop_predicates()
- 8212243: More gc interface tweaks for arraycopy
- 8213384: Move G1/C2 barrier verification into G1BarrierSetC2
- 8213381: Hook to allow GC to inject Node::Ideal() calls
- 8213371: GC/C2 abstraction and cleanup to handle custom offset for GC
memory accesses
- 8213469: Remove/fix leftovers from JDK-8213384: Move G1/C2 barrier
verification into G1BarrierSetC2

all of which amounts to much-reduced upstream diff in C2 land.

Testing: tier3_gc_shenandoah fastdebug/release (x86)
(might need extra testing on aarch64 because we had some conflicts there
in the various CAS matchers in C2)

I needed to add this to shenandoahCodeRoots.cpp:
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp
b/src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp
@@ -205,6 +205,7 @@
       break;
     }
     case 2: {
+      ResourceMark rm;
       ShenandoahNMethodOopDetector detector;
       nm->oops_do(&detector, /* allow_zombie = */ true);



Because of ShenandoahNMethodOopDetector allocating a GrowableArray as
resource. Not sure why this started failing now, and not earlier and if
needs backporting.

Ok?

Roman