The bias for the PT_GNU_EH_FRAME was using the paddr instead of vaddr.
This doesn't match the way the load bias is calculated, which always
use vaddr - offset, so change to use vaddr.
Found on an old x86 device that has a vdso that sets vaddr differently
from paddr.
Add a new offline test to catch this case and update the elf interface
unit tests.
Also, fix a small bug in the unwind_for_offline tool.
Bug: 142365899
Test: Unit tests pass.
Change-Id: I5f0bf062dd8ee45aa8553189ba493ec962e0b059
5838e53b97