vim-patch:8.0.1465: python2 and python3 detection not tested

Problem:    Python2 and python3 detection not tested. (Matej Cepl)
Solution:   Add test for detecting python2 and python3.  Also detect a script
            using "js" as javascript.
4bc0bed536

src/nvim/testdir/test_filetype.vim

@@ -560,10 +560,13 @@ let s:script_checks = {
       \ 'perl6': [['#!/path/perl6']],
       \ 'perl': [['#!/path/perl']],
       \ 'php': [['#!/path/php']],
-      \ 'python': [['#!/path/python']],
+      \ 'python': [['#!/path/python'],
+      \            ['#!/path/python2'],
+      \            ['#!/path/python3']],
       \ 'groovy': [['#!/path/groovy']],
       \ 'ruby': [['#!/path/ruby']],
       \ 'javascript': [['#!/path/node'],
+      \                ['#!/path/js'],
       \                ['#!/path/nodejs'],
       \                ['#!/path/rhino']],
       \ 'bc': [['#!/path/bc']],