- Remove TruncateInt64ToInt32 instead of translating to Turboshaft, since it has no effect. Removing it simplifies pattern-matching in optimizations.
- Change how exception handling is done in Turboshaft: The exception value is obtained as the result of `CatchExceptionOp` instead of a special projection. This simplifies projections.
- Add `TupleOp` as the counterpart to `ProjectionOp`, which is useful
  for lowerings of operations that have multiple outputs.

- Split BinopOp into WordBinopOp and FloatBinopOp because they have quite different semantics and many kinds only exist for one of them.
- rename IntegerUnary to WordUnary and other occurences of
  Integer/Integral
- rename ChangeOp::Kind::kUnsignedFloatTruncate` to `kJSFloatTruncate`
  because it actually has JS wrap-around semantics.
- move/add representation DCHECKs to operation constructors.
- add some convinience helpers to `AssemblerInterface`.

- Add a mechanism to check which operations are supported by the machine.

Drive-by fix: Abort current block in OptimizationPhase::VisitBlock if
  we lower to a block-terminator.

Bug: v8:12783
Change-Id: Ib738accccd22fb1606d9dab86f57ac1e739fcec2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3857449
Auto-Submit: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Darius Mercadier <dmercadier@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82857}