This introduces a class which can be used for formatting dynamic values
into a constant-size, stack-allocated array. You get ostream-style code
but printf-style performance, and in particular no dynamic allocation.
This makes this class also suitable to be used in OOM or other fatal
situations where we cannot rely on dynamic memory allocation to still
work.

Using FormattedString will automatically compute the format string
depending on the types. It also computes the maximum size of the output.
Last but not least, it makes the code a lot more readable than
traditional printf style printing.

R=mlippautz@chromium.org

Bug: chromium:1323177
Change-Id: I47228b3603c694c1fa23516dd3f1c57e39c0ca35
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3644622
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80529}