Remove obsolete test.

Actually, after the previous commit the code in executable.rb does no longer use `ENV['TM_BUNDLE_SUPPORT']` at all, so we can simplify the test setup and also remove one test case completely.

Support/test/test_executable.rb

@@ -14,9 +14,7 @@ def setup
     ENV['HOME'] = "#{__dir__}/fixtures/sample_project"
     ENV.delete_if{ |name, _value| name.start_with?('TM_') }
 
-    # $TM_BUNDLE_SUPPORT is needed by `Executable.determine_rvm_prefix`
-    ENV['TM_BUNDLE_SUPPORT'] = File.realpath("#{__dir__}/..")
-    @rvm_prefix = "#{ENV['TM_BUNDLE_SUPPORT']}/bin/rvm_wrapper"
+    @rvm_prefix = "#{File.realpath("#{__dir__}/..")}/bin/rvm_wrapper"
   end
 
   def teardown
@@ -144,14 +142,6 @@ def test_missing_executable_with_rbenv_and_shim
     end
   end
 
-  def test_rvm_when_used_from_another_bundle
-    with_rvm_installed do
-      with_env('TM_BUNDLE_SUPPORT' => '/some/other/bundle', 'TM_RUBY_BUNDLE_SUPPORT' => ENV['TM_BUNDLE_SUPPORT']) do
-        assert_equal %W(#{@rvm_prefix} bin/rspec), Executable.find('rspec')
-      end
-    end
-  end
-
   def test_find_precedence
     # Make sure we start with a directory with no Gemfile or binstubs, and also with no environment variable.
     Dir.mktmpdir do |dir|