Slow down memory_limit test
Slow down memory_limit test

Otherwise the test may execute so fast, that the
watchdog thread, ticking at 10ms currently, is too
slow to detect the memory limit situation.

php/pecl-languages-v8js,uniconstructor/v8js,dayed/v8js,ABaldwinHunter/v8js-clone,dayed/v8js,rosmo/v8js,dayed/v8js,php/pecl-languages-v8js,php/pecl-languages-v8js,zzhh9857/v8js,preillyme/v8js,stesie/v8js,stesie/v8js,phpv8/v8js,uniconstructor/v8js,zzhh9857/v8js,ABaldwinHunter/v8js-clone,preillyme/v8js,rosmo/v8js,rosmo/v8js,zzhh9857/v8js,preillyme/v8js,ABaldwinHunter/v8js-clone,stesie/v8js,rosmo/v8js,uniconstructor/v8js,stesie/v8js,phpv8/v8js,zzhh9857/v8js,uniconstructor/v8js,phpv8/v8js,dayed/v8js,php/pecl-languages-v8js,preillyme/v8js,ABaldwinHunter/v8js-clone