Removes some unneeded lints, especially `#[allow(unsafe_code)]`.
Testing: Refactor
Part of: #40383
Signed-off-by: WaterWhisperer <waterwhisperer24@qq.com>
Moves interfaces defined by the performance spec to the
`script/dom/performance/` module from `script/dom/`.
Testing: Just a refactor shouldn't need any testing
Fixes: Partially #38901
Signed-off-by: WaterWhisperer <waterwhisperer24@qq.com>