This reverts commit 93a8ebac2d6eb124bf57223069765af08fcd5c85, now that
fce604c8ae11b462113305aba080d77f8193cfea "[API CHANGE] return unsigned 64-bit
value from GetSystemTicks in basic code" is in.
Introduced with 060c2b9b1b0d3c9cf27f1b289a620cfa82b5b060 "QA Basic: split tests
of methods in different files", but GetSystemTicks appears to routinely return
negative values.
Change-Id: Ibccdf753aea581e05e9d4e1bf551ae72dc70c959