httppeer: properly gate debug usage behind debug flag check The "dbg" local variable is only defined if the 'debugflag' is set to True. However, it was used indiscriminately later in the function. We hide its usage behind the 'debugflag' value to avoid raising a NameError.

test-http-branchmap: fix stdio mode on Windows

test-http-branchmap: fix encoding test to wrap the server stream Wrapping sys.std* streams has no effect since 39d13b8c101d, "py3: bulk replace sys.stdin/out/err by util's."

test-merge-tools: create repo directory to free $TESTTMP for temporary files