Fix test-demandimport and test-trusted under Windows
The Windows-only wrapper around stdout is causing both of these tests to fail.
test-demandimport fails because it tries to print repr(sys.stdout). Use
stderr instead since that is not wrapped.
test-trusted fails because the wrapper doesn't handle softspace and an
unexpected extra space gets printed.
os = <unloaded module 'os'>
os.system = <built-in function system>
os = <module 'os' from '?'>
util = <unloaded module 'util'>
util.system = <function system at 0x?>
util = <module 'mercurial.util' from '?'>
util.system = <function system at 0x?>
fred = <unloaded module 're'>
re = <unloaded module 'sys'>
fred = <unloaded module 're'>
fred.sub = <function sub at 0x?>
fred = <proxied module 're'>
re = <unloaded module 'sys'>
re.stderr = <open file '<stderr>', mode 'w' at 0x?>
re = <proxied module 'sys'>