py3: use r'' to prevent the addition of b'' by transformer There are cases in opts handling in debugcommands.py where we don't need to convert opts keys back to bytes as there are some handful cases and no other function using opts value. Using r'', we prevent the transformer to add a b'' which will keep the value str.

py3: use pycompat.byteskwargs() to convert kwargs' keys to bytes This is used where ever required like where kwargs are passed into ui.formatter(), scmutil.match() or cmdutil.openrevlog() which expects bytes.

tests: use cgienv to minimize environment setup at hgweb tests This patch follows other hgweb tests.

tests: avoid test failure for mangling path-like string by MSYS