rename language tests to use swift extension instead of dtm. make VDLC (which is hopefully now only used in those tests) recognise swift rather than dtm as source file extension.
rename language tests to use swift extension instead of dtm. make VDLC (which is hopefully now only used in those tests) recognise swift rather than dtm as source file extension.

git-svn-id: 6ee47c8665bf46900d9baa0afb711c5b4a0eafac@1627 e2bb083e-7f23-0410-b3a8-8253ac9ef6d8

ya7lelkom/swift-k,ya7lelkom/swift-k,ya7lelkom/swift-k,swift-lang/swift-k,swift-lang/swift-k,ya7lelkom/swift-k,ya7lelkom/swift-k,swift-lang/swift-k,swift-lang/swift-k,ya7lelkom/swift-k,ya7lelkom/swift-k,swift-lang/swift-k,ya7lelkom/swift-k,swift-lang/swift-k,swift-lang/swift-k,swift-lang/swift-k,swift-lang/swift-k,ya7lelkom/swift-k,ya7lelkom/swift-k,swift-lang/swift-k