Remove 'test' message and `pwd` showing what directory they are in.

git-size-diff.sh won't run if the pwd of the directory doesn't have a git
repository in it. If it runs, they obviously know what pwd is, so don't
output it.

testing:
-ran 'git size-diff' on this change and put it below 'git-size-diff:'

modified:   bin/git-size-diff.sh

git-size-diff:
 bin/git-size-diff.sh |    3 ---
 1 file changed, 3 deletions(-)