Rollup merge of #135476 - kleisauke:remove-asmjs-remnant, r=Kobzol

Remove remnant of asmjs

See: https://github.com/rust-lang/rust/issues/131467#issuecomment-2529314603.

src/ci/docker/scripts/emscripten.sh

@@ -1,24 +0,0 @@
-#!/bin/sh
-set -ex
-
-hide_output() {
-  set +x
-  on_err="
-echo ERROR: An error was encountered with the build.
-cat /tmp/build.log
-exit 1
-"
-  trap "$on_err" ERR
-  bash -c "while true; do sleep 30; echo \$(date) - building ...; done" &
-  PING_LOOP_PID=$!
-  "$@" &> /tmp/build.log
-  trap - ERR
-  kill $PING_LOOP_PID
-  rm -f /tmp/build.log
-  set -x
-}
-
-git clone https://github.com/emscripten-core/emsdk.git /emsdk-portable
-cd /emsdk-portable
-hide_output ./emsdk install 3.1.68
-./emsdk activate 3.1.68