Fix DWARF locations when we have large .dwp files. (#87164)

We have the ability to load .dwp files with a .debug_info.dwo section
that exceeds 4GB. There were 4 locations that were using 32 bit offsets
and lengths to extract variable locations, and if a DIE was over the 4GB
barrier, we would truncate the block offset for the variable locations
and the variable expression would be garbage. This fixes the issues. It
isn't possible to add a test for this as we don't want to create a 4GB
.dwp file on test machines.