This is a reland of 45227ffd
Differences:
- Handle one more flags conflict in variants.py.
- Disallow %VerifyType without --concurrent-recompilation.

Original change's description:
> [turbofan] extend type asserts to cover all JS types
>
> Extend type assertions to all types covering JavaScript values.
> This is achieved by allocating type representations on the heap using
> newly defined HeapObject subclasses. To allocate these in the compiler,
> we disable concurrent compilation for the --assert-types flag for now.
>
> Fix two type errors that came up with the existing tests:
> 1. JSCreateKeyValueArray has type Array (i.e., a JSArray) instead of
>    OtherObject.
> 2. OperationTyper::NumberToString(Type) can type the result as the
>    HeapConstant Factory::zero_string(). However, NumberToString does
>    not always produce this string. To avoid regressions, the CL keeps
>    the HeapConstant type and changes the runtime and builtin code to
>    always produce the canonical "0" string.
>
> A few tests were failing because they check for truncations to work
> and prevent deoptimization. However, AssertType nodes destroy all
> truncations (which is by design), so these tests are incompatible
> and now disabled for the assert_types variant.
>
> Drive-by fix: a few minor Torque issues that came up.
>
> Change-Id: If03b7851f7e6803a2f69edead4fa91231998f764
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3234717
> Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#77565}

Change-Id: I5b3c6745c6ad349ff8c2b199d9afdf0a9b5a7392
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3247035
Auto-Submit: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77596}