Bye, Bye Compaction Tables. The benefit compaction tables provides doesn't

outweight its computational costs. This patch removes all compaction
table handling from the bcreader and bcwriter. For the record, here's the
difference betweeen having and not having compaction tables for some tests:

Test             With       Without   Size Chg
Olden/mst       5,602         5,598      +0.1%
viterbi        18,026        17,795      +1.3%
obsequi       162,133       166,663      -2.8%
burg          224,090       228,148      -1.8%
kimwitu++   4,933,263     5,121,159      -3.8%
176.gcc     8,470,424     9,141,539      -7.3%

It seems that it is more beneficial to larger files, but even on the largest
test case we have (176.gcc) it only amounts ot an I/O saving of 7.3%.

llvm-svn: 33661