Use standard llvm Debug.h support for debugging output.
Use standard llvm Debug.h support for debugging output.

Leave a quick "// Uncomment this." hint to enable the debug output in
tests. FIXME: figure out whether we want to enable debug command line
handling for all tests.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@172608 91177308-0d34-0410-b5e6-96231b3b80d8

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