hghave: adjust the definition of `tic` to allow curses tests on Windows

hghave: adjust the definition of `tic` to allow curses tests on Windows

Might as well pick up the test coverage if it works as-is.

Differential Revision: https://phab.mercurial-scm.org/D9808

--- a/tests/hghave.py	Wed Dec 09 00:51:35 2020 -0500
+++ b/tests/hghave.py	Sun Jan 17 02:50:26 2021 -0500
@@ -708,6 +708,12 @@
         import curses
 
         curses.COLOR_BLUE
+
+        # Windows doesn't have a `tic` executable, but the windows_curses
+        # package is sufficient to run the tests without it.
+        if os.name == 'nt':
+            return True
+
         return matchoutput('test -x "`which tic`"', br'')
     except (ImportError, AttributeError):
         return False