The correct way to run Python when building Servo is `uv run python`,
unless we are running as a descendant of `uv run python`. In that case,
we can use either `uv run python` or `python` (uv does not provide a
`python3` on Windows \*).
\* for the astute reader, yes, this causes problems for mozjs, which
only tries `python3` unless PYTHON3=python :)))
Testing: tested manually on macOS 13 (see below), and will be tested in
CI
Fixes: #37289

Signed-off-by: Delan Azabani <dazabani@igalia.com>
These changes make our implementation of the enumeration hook for
globals [match
Gecko's](https://searchfox.org/mozilla-central/rev/1f65969e57c757146e3e548614b49d3a4168eeb8/dom/base/nsGlobalWindowInner.cpp#3297),
fixing an assertion failure that occurred in the previous
implementation.
Our enumeration hook is supposed to fill a vector with names of
properties on the global object without modifying the global in any way;
instead we were defining all of the missing webidl interfaces. We now do
much less work and crash less.
Testing: New crashtest based on manual testcase.
Fixes: #34686
---------
Signed-off-by: Josh Matthews <josh@joshmatthews.net>