readlink/MYDIR standardization

Convert shell scripts to use readlink to get the current dir and use a
function helper to switch to using greadlink on MacOS.

Also fix any scripts using 'readlink --canonicalize' to use
'readlink -f' as containers having busybox's readlink don't have
--canonicalize.

Change-Id: I8c82d4e03f3953c2489c4da3f7700de0ff0f3e0c
2 files changed