emscripten: send fake mouse events for touches, like other targets do. (This really should be handled at the higher level and not in the individual targets, but this fixes the immediate bug.)

#!/bin/bash
./testharness.exe --config testsprite2_crashtest.config > testrun.log 2>&1
if [ "$?" != "0" ]; then
  echo TEST RUN FAILED (see testrun.log)
  # report error code to CI
fi