[arm64] Add DCHECK for negative stack pointer offset

Negative offsets from the stack pointer are prohibited by the
simulator so add a check to catch this at compile time.

This DCHECK is currently tripped by the
v8_enable_builtins_profiling and
--turbo_force_mid_tier_regalloc flags
causing the mid-tier register allocator to be used.

Bug: chromium:1299793
Change-Id: I0d11e584178cc08a500e563fa213737a93b10bad
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3483660Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Martyn Capewell <martyn.capewell@arm.com>
Cr-Commit-Position: refs/heads/main@{#79238}

src/compiler/backend/arm64/code-generator-arm64.cc

@@ -255,6 +255,9 @@ class Arm64OperandConverter final : public InstructionOperandConverter {
         offset = FrameOffset::FromStackPointer(from_sp);
       }
     }
+    // Access below the stack pointer is not expected in arm64 and is actively
+    // prevented at run time in the simulator.
+    DCHECK_IMPLIES(offset.from_stack_pointer(), offset.offset() >= 0);
     return MemOperand(offset.from_stack_pointer() ? sp : fp, offset.offset());
   }
 };