[lld] r249752 - Revert: r249728 - Roll back r249726 and r249723 because they broke buildbots.

[Rafael Espíndola via llvm-commits]

> Alan Modra @ IBM was kind enough to do some research on my behalf, and binutils has set TEXT_START_ADDR=0x10000000 in elf64ppc.sh since 1999. This was done to implement this suggestion in the PPC64 ELF ABI (http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html):

Awesome!

>   It is normally desirable to put segments with different characteristics in separate 256 Mbyte portions of the address space, to give the operating system full paging flexibility in the 64-bit address space.
>
> And the lowest non-zero 256M boundary is 0x10000000.

Interesting. Do you know what "characteristics" they are referring to?
It cannot be permissions, otherwise we would need to align segments to
256MB.

In any case. That is sufficient IMHO to have the target specific VA
support. I would only ask that we use the TargetInfo constructor to
set the current value and only the ppc64 one changes the value and
references the above spec.

Thanks,
Rafael