patch 8.2.1631: test_fails() does not check the context of the line number

Problem:    test_fails() does not check the context of the line number.
Solution:   Use another argument to specify the context of the line number.
diff --git a/src/evalfunc.c b/src/evalfunc.c
index e69f293..619abba 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -495,7 +495,7 @@
     {"assert_equal",	2, 3, FEARG_2,	  ret_number,	f_assert_equal},
     {"assert_equalfile", 2, 3, FEARG_1,	  ret_number,	f_assert_equalfile},
     {"assert_exception", 1, 2, 0,	  ret_number,	f_assert_exception},
-    {"assert_fails",	1, 4, FEARG_1,	  ret_number,	f_assert_fails},
+    {"assert_fails",	1, 5, FEARG_1,	  ret_number,	f_assert_fails},
     {"assert_false",	1, 2, FEARG_1,	  ret_number,	f_assert_false},
     {"assert_inrange",	3, 4, FEARG_3,	  ret_number,	f_assert_inrange},
     {"assert_match",	2, 3, FEARG_2,	  ret_number,	f_assert_match},