This reverts commit f52bcaa27f.
It did not pass CI, and was merged anyway because there were two CI
errors in the same cygwin job. The other error was not the fault of this
commit, and since cygwin errors were glossed over because they were
"expected", the presence of a new error *added* by this commit was
overlooked.
Per the meson development policy, PRs which result in CI errors
can/should be reverted at will, no questions asked.
With this change File objects created with the builtin files() function
can be used with the fs submodule like normal strings.
All methods that seem reasonable support FileOrSting arguments.
For example fs.exists() still only takes str arguments because meson
already ensures that File objects do exist when creating them with files().
Each user facing function of the fs module has an additional FeatureNew
check when used with File objects.
The test cases for fs are extended appropriately with tests for File objects.