Remove the eSymbolTypeFunction, eSymbolTypeGlobal, and eSymbolTypeStatic.

They will now be represented as:
eSymbolTypeFunction: eSymbolTypeCode with IsDebug() == true
  eSymbolTypeGlobal: eSymbolTypeData with IsDebug() == true and IsExternal() == true
  eSymbolTypeStatic: eSymbolTypeData with IsDebug() == true and IsExternal() == false

This simplifies the logic when dealing with symbols and allows for symbols
to be coalesced into a single symbol most of the time.

Enabled the minimal symbol table for mach-o again after working out all the
kinks. We now get nice concise symbol tables and debugging with DWARF in the
.o files with a debug map in the binary works well again. There were issues
where the SymbolFileDWARFDebugMap symbol file parser was using symbol IDs and
symbol indexes interchangeably. Now that all those issues are resolved 
debugging is working nicely.

llvm-svn: 113678