This CL unifies how stack checks are handled in the Turbofan pipeline
across architectures, in preparation for properly handling stack
overflows caused by deoptimization in follow-up work. It will also
open up possibilities to simplify related logic.

How this used to work: JSStackCheck was lowered to a UintLessThan
with the stack pointer (sp) and stack limit as inputs. On x64 and ia32,
this node pattern was later recognized during instruction selection
and rewritten to dedicated operators. On other platforms, including
arm and arm64, special logic exists to avoid useless
register-to-register moves when accessing the sp.

This CL introduces a new StackPointerGreaterThan operator, which takes
the stack limit as its sole input. This is what JSStackCheck now lowers
to. This is threaded through to code generation, where we emit the
appropriate code (in the future, we will apply an additional offset to
the sp here).

In follow-up CLs, we can remove or replace remaining uses of
LoadStackPointer in CSA, Wasm, and the interpreter; and then remove
the LoadStackPointer operator, related node matchers, related register
constraints, and the pseudo-smi stack limit roots.

Bug: v8:9534
Change-Id: I0e3f1beeed65b163c4ee5787600bed8c3cc671e1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1738863Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63156}