Currently, it is possible to declare macros, builtins, etc., without
specifying a return type, in which case the return type is treated as
void. This is confusing; the code is more clear if we require the return
type to be specified.

Aside from src/torque, this change is almost entirely just adding
`: void` until the compiler is happy. However, two intrinsics in
src/builtins/torque-internal.tq have been corrected to declare an
appropriate return type. Those two intrinsics were only used in code
generated within the compiler after the type-checking phase, so we never
noticed that their return types were declared incorrectly.

Bug: v8:7793
Change-Id: Ib7df88678c25393a9e3eba389a6a1c4d9233dcbb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3176502
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77178}