[ELF] - Fixed 3 testases failtures on win32 configuration.

Had 3 testcases failtures:
ELF/eh-frame-merge.s 
ELF/gc-sections-eh.s
ELF/gc-sections-lsda.s​

Problem was that OutputOff is size_t, which is 32
for this configuration and next
condition never was checked correctly:

if (PieceI->OutputOff == (uintX_t)-1)
  continue;

llvm-svn: 276296