It used to be possible to do this:
```
bomb = find_program('nonexisting', required: false)
test('traceback during meson test', bomb)
```
and it would in fact bomb out, with:
```
[0/1] Running all tests.
Traceback (most recent call last):
File "/usr/lib/python3.10/site-packages/mesonbuild/mesonmain.py", line 149, in run
return options.run_func(options)
File "/usr/lib/python3.10/site-packages/mesonbuild/mtest.py", line 2017, in run
return th.doit()
File "/usr/lib/python3.10/site-packages/mesonbuild/mtest.py", line 1685, in doit
runners.extend(self.get_test_runner(test) for test in tests)
File "/usr/lib/python3.10/site-packages/mesonbuild/mtest.py", line 1685, in <genexpr>
runners.extend(self.get_test_runner(test) for test in tests)
File "/usr/lib/python3.10/site-packages/mesonbuild/mtest.py", line 1586, in get_test_runner
return SingleTestRunner(test, env, name, options)
File "/usr/lib/python3.10/site-packages/mesonbuild/mtest.py", line 1308, in __init__
self.cmd = self._get_cmd()
File "/usr/lib/python3.10/site-packages/mesonbuild/mtest.py", line 1374, in _get_cmd
test_cmd = self._get_test_cmd()
File "/usr/lib/python3.10/site-packages/mesonbuild/mtest.py", line 1352, in _get_test_cmd
if self.options.no_rebuild and not os.path.isfile(testentry):
File "/usr/lib/python3.10/genericpath.py", line 30, in isfile
st = os.stat(path)
TypeError: stat: path should be string, bytes, os.PathLike or integer, not NoneType
ERROR: Unhandled python exception
This is a Meson bug and should be reported!
```
This is something we explicitly check for elsewhere, for example when
using a not-found program as a command in a custom target or generator.
Check for it when making a test too, and error out with a similar error.
Fixes#10091
7df6c6a728