Merge pull request #1879 from alyssais/formulary_cache_clear

tests: add a missing Tab cache clear

Library/Homebrew/test/formula_installer_test.rb

@@ -61,6 +61,8 @@ class InstallTests < Homebrew::TestCase
       assert_equal 3, bin.children.length
       assert_predicate f.prefix/".brew/testball.rb", :readable?
     end
+  ensure
+    ARGV.reject! { |a| a == "--with-invalid_flag" }
   end
 
   def test_bottle_unneeded_formula_install

Library/Homebrew/test/formulary_test.rb

@@ -110,6 +110,7 @@ class FormularyFactoryTest < Homebrew::TestCase
     keg.uninstall
     formula.clear_cache
     formula.bottle.clear_cache
+    Tab.clear_cache
   end
 
   def test_load_from_contents