1) with busybox wget: Download script below and put for example in /data/local/tmp and chmod to 755. the script will calculate the average download speed to download 100M file from london. Maybe I can add later US servers.
2) with GNU wget. Install it from here . Thanks to @alireza7991 for this. After that go to terminal and type:
wget -O /dev/null http://speedtest.london.linode.com/100MB-london.bin
wget -O /dev/null http://speedtest.wdc01.softlayer.com/downloads/test100.zip