Fix command line GUI test script on the Mac

Remove the -d32 flag from the VM arguments; on some systems
this triggers this error message:

     [java] ------ check
     [java]     [junit] Error occurred during initialization of VM
     [java]     [junit] Could not create the Java virtual machine.
     [java]     [junit] Could not reserve enough space for object heap

Also clean out old results files when starting a new test run.

Change-Id: I120db8deae3336d1d44383d93bd1d7b883e0b024
(cherry picked from commit ac6cebca147da897cce0c74d4aac2f54254b61ed)
Merge "Fix command line GUI test script on the Mac"