Enable some unittests on FreeBSD.

test__locale: add typical POSIX-style full locale names.
test_locale: use en_US.US-ASCII on FreeBSD.
diff --git a/Lib/test/test_locale.py b/Lib/test/test_locale.py
index 87c66e9..9187c9e 100644
--- a/Lib/test/test_locale.py
+++ b/Lib/test/test_locale.py
@@ -6,9 +6,12 @@
     raise TestSkipped("Locale support on MacOSX is minimal and cannot be tested")
 oldlocale = locale.setlocale(locale.LC_NUMERIC)
 
-tloc = "en_US"
-if sys.platform[:3] == "win":
+if sys.platform.startswith("win"):
     tloc = "en"
+elif sys.platform.startswith("freebsd"):
+    tloc = "en_US.US-ASCII"
+else:
+    tloc = "en_US"
 
 try:
     locale.setlocale(locale.LC_NUMERIC, tloc)