Keep list of dex files for oat file in CompilerDriver.

Use this list to improve invoke-static/-direct dispatch for
intra-oat calls.

Also fix a latent ArmBaseRelativePatcher::ReserveSpaceEnd()
bug exposed by a buggy early version of this CL: when we
have unresolved patches at the end of all code, we need to
emit a final thunk. Though the OatWriter will try to patch
the unresolved call to a trampoline at the beginning of the
oat file, that trampoline may be too far and the relative
patcher doesn't know about it anyway, so it needs to assume
that a thunk is needed.

This reduces the overall size of oat files present in dalvik
cache on Nexus 9 after first boot by over 1MiB, AOSP ToT,
aosp_flounder-userdebug build.

Change-Id: I98604b70cb17377eed057c1c23971865cf344e43