run_project_tests: Fix Cython compiler detection

On Debian systems the cython compiler binary is installed as
`cython3`. The current logic for detecting whether to run the Cython
unit tests instead checks for `cython` or the value of the `CYTHON`
environment variable, which leads to cases where the underlying Meson
can correctly compile Cython code but the test harness excludes these
tests from execution because it cannot find `cython3`.

This commit makes the test harness use the same detection method as
Meson itself. It also takes the opportunity to refactor some existing
code which does the same job for Objective C and Objective C++ tests
to avoid repetition.

0 files changed, 0 insertions, 0 deletions