JIT: Fix call flag propagation for GenTreeArrElem (dotnet/coreclr#20660)

JIT: Fix call flag propagation for GenTreeArrElem (dotnet/coreclr#20660)

Closes dotnet/coreclr#20651.

Also fix up some "near miss" cases for GenTreeField and GenTreeBoundsCheck,
where we get lucky and the importer currently splits trees with temps so the
currently ignored child nodes have no interesting side effects.

Revise GenTreeField a bit to pull more of the initialization work into the
constructor. Add a missing R2R field propagation for field nodes in GtClone
(evidently also never hit in practice).

Commit migrated from https://github.com/dotnet/coreclr/commit/626def86af589734999a0e62d3a83c2acb9de54a