The workaround stopped working because JSEvents is now not a global
object. Update the workaround by exporting the JSEvents object from
emscripten runtime and replacing the function that removes the
event handlers to a dummy function that does nothing temporarily, only
to revert it when the context is destroyed.
Fixes: QTBUG-107197
Pick-to: 6.4
Change-Id: Icceae884c85e04fdafcca6cf3c563094d3f6f0dc
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
Mikolaj Boc