Refactor paths to Android Runtime binaries in directory `cmds/installd/`.

Have `dexopt` and `otapreopt` use the same set of definitions.

Test: A/B OTA update test (asit/dexoptota/self_full).
Bug: 113373927
Bug: 120796514
Change-Id: I94e55a831c68b67cb81cfa91281b2feb0cc4b365