Emscripten only supports
SSE1, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, and 128-bit AVX instruction
sets at this time.
https://emscripten.org/docs/porting/simd.html
Browsers might need to enable simd support in the advanced
configurations
about: config or chrome:flags
Enable by configuring Qt with -sse2
Pick-to: 6.2
Fixes: QTBUG-63924
Change-Id: Ifeafae20e199dee0d19689802ad20fd0bd424ca7
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>