Disable .toc optimization for host modules.

Host binaries may be run during the build process and the internal
implementation of the shared libraries makes a difference for the build
result. This change makes sure host tools get re-linked and re-run when
any of its dependency libraries gets updated.
DEX2OAT is such a host tool. We also changed DEX2OAT as full dependency
of dex-preoptimization, so we rebuild the odex files if DEX2OAT itself,
or any dependency libraries changed.

Bug: 24597504
Change-Id: Idf0d9be82ccebd826d9c5b405a39cff437e0af29