<rdar://problem/9958446>

<rdar://problem/10561406>

Stopped the SymbolFileDWARF::FindFunctions (...) from always calculating
the line table entry for all functions that were found. This can slow down
the expression parser if it ends up finding a bunch of matches. Fixed the 
places that were relying on the line table entry being filled in.

Discovered a recursive stack blowout that happened when "main" didn't have
line info for it and there was no line information for "main"

llvm-svn: 146330