Enable syscall_test on windows.

Enable syscall_test on windows.

This test has been disabled under windows since it was first
added which left these syscalls untested.

I had to remove the regex_filter from this command as it
was not be parsed correctly by the windows command line.
However these tests pass which means that no other stderr
lines are output by the test.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3808
TEST= run_syscall_test
R=mseaborn@chromium.org

Committed: https://src.chromium.org/viewvc/native_client?view=rev&revision=12878

[Mark Seaborn, 2014-03-11 21:34:40]

LGTM, thanks

[Sam Clegg, 2014-03-12 20:34:20]

Worked around an issue caused by UNICODE be inconsistenly defined (use
WIN32_FIND_DATAW rather than WIN32_FIND_DATA in nacl_host_dir_types.h so the
struct is always the same size).

[Mark Seaborn, 2014-03-12 21:08:20]

LGTM

[Sam Clegg, 2014-03-12 21:25:52]

Committed patchset #3 manually as r12878 (presubmit successful).