Support trailing slash in pathtools.Match patterns

pathtools.Match was trimming the trailing slash from patterns.  Make
it handle a trailing slash by first confirming that both the pattern
and name either both have or both do not have a trailing slash, and
then trimming it from both.

Bug: 111389216
Test: TestMatch in glob_test.go
Change-Id: I743e00c14d885de5b5a060aa9e2b22c81dc7e09d