Bundled libjpeg-turbo should be built with SIMD enabled

When the bundled legacy libjpeg was replaced with libjpeg-turbo, it was done without including and enabling  the SIMD extensions. This is not recommended by the libjpeg-turbo maintainers and suboptimal because

1. libjpeg-turbo is by default built with those extensions, hence those code paths are the most well tested (ref. e.g. linked Jira issue)
2. Enabling the extensions increases performance.