[wasm] Disable loop unrolling by default

We are disabling loop unrolling for wasm until we find a solution to
some stability problems.

Bug: v8:11298, chromium:1184929
Change-Id: I21c66d37b1606175a5ed44b6db0269651da1f3c7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2780298
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73622}

src/flags/flag-definitions.h

@@ -945,7 +945,7 @@ DEFINE_BOOL(wasm_stack_checks, true,
 DEFINE_BOOL(wasm_math_intrinsics, true,
             "intrinsify some Math imports into wasm")
 
-DEFINE_BOOL(wasm_loop_unrolling, true,
+DEFINE_BOOL(wasm_loop_unrolling, false,
             "enable loop unrolling for wasm functions (experimental)")
 DEFINE_BOOL(wasm_trap_handler, true,
             "use signal handlers to catch out of bounds memory access in wasm"