phpunit: Remove PHPUnit_Util_Log_JSON which spammed to stdout on console

`PHPUnit_Util_Log_JSON` currently spams to stdout making PHPUnit basically unusable from the console. See https://gist.github.com/bantu/b311ec2bec73c6a96816

This patch removes `PHPUnit_Util_Log_JSON`.

Alternative patch to #3846 as requested by @MTGap.