Don't depend on lld creating relocations in ro segments.

We currently don't do a good job of diagnosing inputs that would require
dynamic relocations to be applied to read only segments.

I am about to improve lld in that area, but unfortunately we developed
tests that depend on the current behavior.

To make clear what is actually changing, this first patch just updates
tests to not depend on the current behavior. In most cases this just
means using a rw section instead of a ro one, but that unfortunately
changes many addresses.

llvm-svn: 268145