Fix description on how to run the tests

As of commit 8af91fd all tests are
PHPTs, and make_phpt has been removed.  We adjust the docs accordingly.

Author: cmb69

tests/README.md

@@ -4,11 +4,6 @@ If you pass this suite, you aren't necessarily spec compliant, but it is a helpf
 
 ## Usage
 
-To run using the PHP5 test runner, you'll need to convert to PHP5's .phpt format first.  The following demonstrates writing the tests out to /tmp/phpt:
+To run using the PHP test runner, do something like:
 
-    ./make_phpt . /tmp/phpt
     TEST_PHP_EXECUTABLE=~/php-src/sapi/cli/php ~/php-src/run-tests.php /tmp/phpt
-
-To use the HHVM test runner:
-
-    ~/hhvm/hphp/test/run .