tests: add new test for #! shebang lines

* use #!/bin/sh not e.g. #!/usr/bin/sh
* use #!/usr/bin/env python not e.g. #!/usr/bin/python

tests/test-check-shbang.t

@@ -1,23 +1,13 b''
-#require test-repo execbit
+#require test-repo
 
   $ cd "`dirname "$TESTDIR"`"
 
-look for python scripts without the execute bit
+look for python scripts that do not use /usr/bin/env
 
-  $ hg files 'set:**.py and not exec() and grep(r"^#!.*?python")'
-  [1]
-
-look for python scripts with execute bit but not shebang
-
-  $ hg files 'set:**.py and exec() and not grep(r"^#!.*?python")'
+  $ hg files 'set:grep(r"^#!.*?python") and not grep(r"^#!/usr/bin/env python")'
   [1]
 
-look for shell scripts with execute bit but not shebang
-
-  $ hg files 'set:**.sh and exec() and not grep(r"^#!.*(ba)?sh")'
-  [1]
+look for shell scripts that do not use /bin/sh
 
-look for non scripts with no shebang
-
-  $ hg files 'set:exec() and not **.sh and not **.py and not grep(r"^#!")'
+  $ hg files 'set:grep(r"^#!.*/bin/sh") and not grep(r"^#!/bin/sh")'
   [1]