Multi threaded hashed deduplication during compilation.

Moved deduplication to be in the compiler driver instead of oat
writer. This enables deduplication to be performed on multiple
threads. Also added a hash function to avoid excessive comparison
of byte arrays.

Before (alloats host):
real	1m6.967s
user	4m22.940s
sys	1m22.610s

Thinkfree.apk (target mako):
0m23.74s real     0m50.95s user     0m9.50s system
0m24.62s real     0m50.61s user     0m10.07s system
0m24.22s real     0m51.44s user     0m10.09s system
0m23.70s real     0m51.05s user     0m9.97s system
0m23.50s real     0m50.74s user     0m10.63s system

After (alloats host):
real	1m5.705s
user	4m44.030s
sys	1m29.990s

Thinkfree.apk (target mako):
0m23.32s real     0m51.38s user     0m10.00s system
0m23.49s real     0m51.20s user     0m9.80s system
0m23.18s real     0m50.80s user     0m9.77s system
0m23.52s real     0m51.22s user     0m10.02s system
0m23.50s real     0m51.55s user     0m9.46s system

Bug: 10552630

Change-Id: Ia6d06a747b86b0bfc4473b3cd68f8ce1a1c7eb22
17 files changed