Update emscripten.yml

Author: mcbarton

.github/workflows/emscripten.yml

@@ -694,7 +694,7 @@ jobs:
                 -DSYSROOT_PATH=$SYSROOT_PATH                     \
                 ../
         fi
-        emmake make -j ${{ env.ncpus }} check-cppinterop
+        EMCC_CORES=2 emmake make -j 2 check-cppinterop
         cd ./unittests/CppInterOp/
         # Explaination of options for emrun
         # --browser (name of browser on path)