Several changes here:

1. Increase max node size from 64->256 to avoid collapsing an important
   structure in 181.mcf
2. If we have multiple calls to an indirect call node with an indirect
   callee, fold these call nodes together, to avoid DSA turning apoc into
   a flaming fireball of death when analyzing 176.gcc.
  With this change, 176.gcc now takes ~7s to analyze for loc+bu+td, with
  5.7s of that in the BU pass.

llvm-svn: 20775