Remove bad test

Library/Homebrew/test/test_formula.rb

@@ -242,16 +242,6 @@ class FormulaTests < Homebrew::TestCase
     assert_equal PkgVersion.parse('HEAD'), f.pkg_version
   end
 
-  def test_raises_when_non_formula_constant_exists
-    const = :SomeConst
-    Object.const_set(const, Module.new)
-    begin
-      assert_raises(FormulaUnavailableError) { Formulary.factory("some_const") }
-    ensure
-      Object.send(:remove_const, const)
-    end
-  end
-
   def test_legacy_options
     f = formula do
       url "foo-1.0"