Rename fields in dexpreopt config

Add 'host' into the name of fields regarding path on the host side to
distinguish between paths on the device(which will be added in the
following commit), and paths on the host.

Bug: 158843648
Test: build and flash, and then
  adb wait-for-device \
    && adb -s $S root \
    && adb -s $S logcat \
    | grep -E 'ClassLoaderContext [a-z ]+ mismatch' -C 1
Change-Id: Ib2645ed51591ba2f4b726c115b401ad2bd6675da