This matches the tests for Python extensions.
Also include some other cleanups to these `meson.build` files:
Adding `python_dep` is no longer needed, this is automatic now.
Use a single line for `import('python').find_installation()`,
because the result of `import('python')` by itself is not used
for anything.
D lang compilers have an option -release (or similar) which turns off
asserts, contracts, and other runtime type checking. This patch wires
that up to the b_ndebug flag.
Fixes#7082
This doesn't touch everything as it's just based on the python3 module
tests, ported to the python module. It's still better than the one very
basic test in the unit test module.
Ralf Gommers
Dylan Baker
Jussi Pakkanen