Add support of lzcnt and tzcnt - support of lzcnt and tzcnt instructions, - unit tests for lzcnt/tzcnt, - ability to emit bsf/bsr in case lzcnt/tzcnt were turned off from the command line, - tightening the stamps produced by ScanBitForward/ReverseNode nodes. Contributed-By: Igor Veresov <igor.veresov@oracle.com>

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