Remove redundant test

Author: hadley

tests/testthat/_snaps/signal.md

@@ -9,10 +9,3 @@
     Output
       <lifecycle_stage: foo(arg) is superseded>
 
-# signal_experimental() and signal_superseded() are deprecated
-
-    Code
-      signal_experimental("1.0.0", "foo(arg = )")
-    Code
-      signal_superseded("1.0.0", "foo(arg = )")
-

tests/testthat/test-signal.R

@@ -17,10 +17,3 @@ test_that("signal generates user friendly message", {
     (expect_condition(signal_stage("superseded", "foo(bar)")))
   })
 })
-
-test_that("signal_experimental() and signal_superseded() are deprecated", {
-  expect_snapshot({
-    signal_experimental("1.0.0", "foo(arg = )")
-    signal_superseded("1.0.0", "foo(arg = )")
-  })
-})