0.12.2 RC2: avoid deprecated wasm intrinsics

PiperOrigin-RevId: 376682795

release process: quick test for JPEG XL debug mode (very slow)

PiperOrigin-RevId: 375047518

updated changelog for 0.12

PiperOrigin-RevId: 368673366

Update readme version and compilers tested

PiperOrigin-RevId: 360681785

fix msvc warnings

PiperOrigin-RevId: 358388709

fix unused param

PiperOrigin-RevId: 350389614