Fix a second typo

Author: darakian

schema/support/tests/README.md

@@ -5,7 +5,7 @@ $ node ../Node_validator/validate.js valid/*.json
   ...
   Summary: All files PASSED validation.
 
-# All records in invald directory must fail to validate:
+# All records in invalid directory must fail to validate:
 
 $ node ../Node_validator/validate.js invalid/*.json