This patch adds a perftest for the OONX speecht5-tts q8 quantized model as part of our ongoing exploration and benchmarking of TTS tasks for transform media type project. The goals are 1) add the first perftest for speech-to-text task as reference for future tests; 2) benchmark core performance metrics like latency and memory usage to assess realistic inference conditions (note that streaming audio output is not yet tested. This helps establish a baseline for comparing candidate TTS models (as well as different quantization levels) for future integration decisions. The test runs directly in transformers.js without any modification to the pipeline. Differential Revision: https://phabricator.services.mozilla.com/D248133
=========== mozperftest =========== **mozperftest** can be used to run performance tests against browsers. See the docs directory.