If trap handlers are disabled, we don't need guard regions around wasm
memories. Hence use the dynamic {trap_handler::IsTrapHandlerEnabled()}
check, instead of always reserving guard regions on all 64-bit
platforms.
This will allow to reserve pretty much arbitrarily many wasm memories if
trap handlers are disabled.

Two tests are added to test the number of memories that can be
allocated: With trap handlers, at least 50 memories should always be
possible. Without trap handlers, 10000 small memories should not be a
problem (each one is taking 64kB, so it's 640MB overall).

Drive-by: Improve tracing.

R=ahaas@chromium.org

Bug: v8:11017
Change-Id: Ic4c620f63dfbef571e64df0b3372b83a1db566ab
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2491034Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70732}