Integrate change #9533 from maintperl into mainline.

Integrate change #9533 from maintperl into mainline.

better fix for change#9517 to accomodate UNC paths like
\\server\share\foo, and paths with trailing backslash
like c:\this\

p4raw-link: @9533 on //depot/maint-5.6/perl: aa5978ee553e6e5cbffd44b8ee9d25a8ff75c771
p4raw-link: @9517 on //depot/maint-5.6/perl: 541b948d383abe4f534f846ff692d582506919cf

p4raw-id: //depot/perl@9536
p4raw-integrated: from //depot/maint-5.6/perl@9535 'copy in'
	utils/perldoc.PL x2p/find2perl.PL (@9517..) 'merge in'
	x2p/s2p.PL (@9517..)