patch 8.2.3854: Vim9: inconsistent arguments for test functions

Problem:    Vim9: inconsistent arguments for test functions.
Solution:   When :def function and script have different arguments use a list
            with two items instead of a separate function.
diff --git a/src/testdir/test_float_func.vim b/src/testdir/test_float_func.vim
index 77687d1..41ae815 100644
--- a/src/testdir/test_float_func.vim
+++ b/src/testdir/test_float_func.vim
@@ -246,7 +246,7 @@
   call assert_equal('123456.7', string(str2float("123'456.7'89", 1)))
 
   call assert_equal(1.2, str2float(1.2, 0))
-  call CheckDefAndScriptFailure2(['str2float(1.2)'], 'E1013: Argument 1: type mismatch, expected string but got float', 'E1174: String required for argument 1')
+  call CheckDefAndScriptFailure(['str2float(1.2)'], ['E1013: Argument 1: type mismatch, expected string but got float', 'E1174: String required for argument 1'])
   call assert_fails("call str2float([])", 'E730:')
   call assert_fails("call str2float({})", 'E731:')
   call assert_fails("call str2float(function('string'))", 'E729:')