patch 8.1.1248: no test for dec mouse

Problem:    No test for dec mouse.
Solution:   Add some tests for dec mouse.  Add "no_query_mouse".
diff --git a/src/os_unix.c b/src/os_unix.c
index 528089b..a78b330 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -5940,7 +5940,8 @@
     if (WantQueryMouse)
     {
 	WantQueryMouse = FALSE;
-	mch_write((char_u *)IF_EB("\033[1'|", ESC_STR "[1'|"), 5);
+	if (!no_query_mouse_for_testing)
+	    mch_write((char_u *)IF_EB("\033[1'|", ESC_STR "[1'|"), 5);
     }
 #endif