downcase php -m output and extension name during test method
downcase php -m output and extension name during test method

Closes #2193.

Signed-off-by: Andy Blyler <e3579b1e47f273529f0f929453e939a68ede9fd1@blyler.cc>

philcook/homebrew-php,mkalkbrenner/homebrew-php,TomK/homebrew-php,dguyon/homebrew-php,ablyler/homebrew-php