Improve dex location canonicalization-related performance.

Eagerly add canonical dex file locations to the OatFile's
primary lookup map in Setup(). This moves the boot.oat work
from every app startup to the zygote initialization. Since
we always ended up initializing the canonical location map
anyway due to the way that we're loading dex files, the lazy
initialization didn't save anything.

Clean up dex file name canonicalization to make sure we
free() the memory returned by realpath() rather than using
std::unique_ptr<> with the default deleter.

Avoid some unnecessary duplicate OatDexFile lookups.

Bug: 16828525
Bug: 17346103

(cherry picked from commit aa4497db59f1eeec954f2ba5da6d458fcdf9b3a4)

Change-Id: Icc4b14ebe903282ca91ce24e33a6d7c75dff991c
13 files changed