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/ex_eval.c b/src/ex_eval.c
index f0ffaff..58088a0 100644
--- a/src/ex_eval.c
+++ b/src/ex_eval.c
@@ -290,7 +290,7 @@
 
 		    // Get the source name and lnum now, it may change before
 		    // reaching do_errthrow().
-		    elem->sfile = estack_sfile();
+		    elem->sfile = estack_sfile(FALSE);
 		    elem->slnum = SOURCING_LNUM;
 		}
 	    }
@@ -549,7 +549,7 @@
     }
     else
     {
-	excp->throw_name = estack_sfile();
+	excp->throw_name = estack_sfile(FALSE);
 	if (excp->throw_name == NULL)
 	    excp->throw_name = vim_strsave((char_u *)"");
 	if (excp->throw_name == NULL)