CI: mingw: Use the official actions for msys2
Because ruby/setup-ruby is affected to test result.
Also includes the prerequisite changes from e4b386e090, 90f8199412,
a443cd012a and 4adb6f6969 (Remove Strawberry Perl pkg-config, misc
system & package info, `cmd` as the default shell, set up msys2
environment variables).
(cherry picked from commit 98ec35899b, adapted to the mingw workflow on ruby_3_3)
5c2a9b2789