[perl #126133] autodie touches its touch_me, make it writable

[perl #126133] autodie touches its touch_me, make it writable

autodie's utime.t touches touch_me, in a git checkout that's fine
since the file is writable, but in a distribution, all files are
read-only by default, and on Win32 the utime() call the test expects
to succeed fails.

Per Sisyphus's note, also make win32/GNUmakefile writable to match the
other Win32 makefiles, since they're often modified to configure the
build.