PHP errors used to not show parameter info consistently.
Make it so that it uses a backtrace to get function info, similar to how
exceptions work.
This makes the docref error functions' parameter argument mostly
vestigal, being used only if allocation fails basically.
Several tests will fail from the fact we include function params.
One annoyance is that _build_trace_args truncates strings according to
exception_string_param_max_len.
See phpGH-12048
Co-authored-by: Tim Düsterhus <tim@bastelstu.be>

This is a useful feature, but enabling it by default requires rewriting
every PHPT file's output section. Since that would be a hellish diff to
make and to review, I think the best option is unfortunately, another
INI option. We can enable this for prod/dev recommended INIs, but make
sure it's disabled for the test runner.
This takes some inspiration from the discussion in phpGH-17056, which has
similar problems to this PR.

If this is not enabled by default for tests (like the fatal error
backtrace RFC), then at least test for it.

Per feedback from Tim on the RFC. Also rationalize the default vs.
recommended INI settings.
This does invert the semantics for the option; the if is changed
accordingly.

Almost certainly a better way to do this...

Avoid a negative which is harder to reason about; matches RFC change

RFC is going towards adding this, but disabling it by default.