Ken pointed out that CBuilder's cleanup is too agrressive

Ken pointed out that CBuilder's cleanup is too agrressive

The Windows compile() and link() methods bizarrely include their own
output files in the list of files to be cleaned up.  Now that they
actually are being cleaned up, this isn't ideal ;-)

Stop compile() and link() from cleaning up their own output, and
reinstate the explicit deletion of those output files in the test
scripts.

p4raw-id: //depot/perl@25225