patch 8.2.1297: when a test fails it's often not easy to see where

Problem:    When a test fails it's often not easy to see what the call stack
            is.
Solution:   Add more entries from the call stack in the exception message.
diff --git a/src/message.c b/src/message.c
index 76ec456..91b2fe2 100644
--- a/src/message.c
+++ b/src/message.c
@@ -461,7 +461,7 @@
 
     if (SOURCING_NAME != NULL && other_sourcing_name())
     {
-	char_u	    *sname = estack_sfile();
+	char_u	    *sname = estack_sfile(FALSE);
 	char_u	    *tofree = sname;
 
 	if (sname == NULL)