Force JIT compilation in 680-checker-deopt-dex-pc-0.

Do not rely on reaching the JIT threshold as this can
take a long time and time out on heavily loaded hosts.

Test: testrunner.py --host -t 680-checker-deopt-dex-pc-0 \
      --runtime-option:-Xjitthreshold:0
Bug: 62611253

Change-Id: Ib180b61744e832779e577c86a39b476cb3856198