4g-iperf3-ul: modified the test to parameterize the number of ue in the test.
Parameterize the iperf3 uplink test for the 4g test suite to execute a
given number of UEs. By default, the number of ue is 1.
Change-Id:
I4b006df04bd1af6c117bcb25e6a6b1609ac732fb