Change DWARFCallFrameInfo from using a vector of AddressRanges to

track the EH FDEs for the functions in a module to using a
RangeDataVector, a more light-weight data structure that only refers
to File addresses.  Makes the initial FDE scan about 3x faster, uses
less memory.
<rdar://problem/13465650> 

llvm-svn: 177585