* test: make checkPlatform negation tests platform-independent
The two multi-valued supportedArchitectures tests added in #11375 used
'current' alongside a value that the negation in the wanted platform
matched on some hosts (e.g. ['linux', 'current'] on Windows expands to
['linux', 'win32'], which is correctly rejected by ['!win32']). Replace
'current' with fixed second values so the multi-value code path is still
exercised without depending on process.platform / process.arch.
* test: mock process.platform / process.arch instead of avoiding 'current'
Restores the more realistic scenario from #11375 where supportedArchitectures
mixes a fixed value with 'current'. Mock process.platform / process.arch
explicitly per test so the result no longer depends on the host CI runner.
Zoltan Kochan
e6aca55bd8