patch 8.0.0907: with cp932 font names might be misinterpreted

Problem:    With cp932 font names might be misinterpreted.
Solution:   Do not see "_" as a space when it is the second byte of a double
            byte character. (Ken Takata)
diff --git a/src/os_mswin.c b/src/os_mswin.c
index 8154549..ef75642 100644
--- a/src/os_mswin.c
+++ b/src/os_mswin.c
@@ -2965,7 +2965,9 @@
 	int	did_replace = FALSE;
 
 	for (i = 0; lf->lfFaceName[i]; ++i)
-	    if (lf->lfFaceName[i] == '_')
+	    if (IsDBCSLeadByte(lf->lfFaceName[i]))
+		++i;
+	    else if (lf->lfFaceName[i] == '_')
 	    {
 		lf->lfFaceName[i] = ' ';
 		did_replace = TRUE;