* Rewrite the test code generation for the unicode normalisation test, making sure that we always write UTF-8 source files.

* Fix failures to print the compilation status for modules with non-ascii names (on Windows).

* Help with remote debugging environment encoding problems in test runs, by extending the output of the "buildenv" pseudo-test.

* Explicitly set I/O encoding for subprocesses in parallel cythonize() runs to make the test runner workers inherit it (instead of defaulting to ASCII in Py2).

* Use a Latin-1 Unicode character in the test for Unicode module names to make it more compatible with Windows file system character sets (such as CP-1252).

* Properly decode source and module file name from the FS encoding in Py2. Previously, with ASCII module names, UTF-8 decoding always worked, but wasn't correct.

* Hack around a distutils 3.[5678] bug on Windows for unicode module names.
https://bugs.python.org/issue39432

* Try to fix cython.inline() on Windows with Py3.8+ where the DLL loading requires an explicit registration of the extension output directory.
Closes GH-3450.