Remove JSON test.

Library/Homebrew/test/json_test.rb

-require "testing_env"
-require "json"
-
-class JsonSmokeTest < Homebrew::TestCase
-  def test_encode
-    hash = { "foo" => ["bar", "baz"] }
-    json = '{"foo":["bar","baz"]}'
-    assert_equal json, JSON.generate(hash)
-  end
-
-  def test_decode
-    hash = { "foo" => ["bar", "baz"], "qux" => 1 }
-    json = '{"foo":["bar","baz"],"qux":1}'
-    assert_equal hash, JSON.parse(json)
-  end
-
-  def test_decode_failure
-    assert_raises(JSON::ParserError) { JSON.parse("nope") }
-  end
-end