Add a test for setting the load address of a module with differing physical/virtual addresses
First attempt at landing D42145 was reverted because it caused test
failures on some android devices. It turned out this was because these
devices had vdso modules with differing physical and virtual addresses.
This was not caught earlier because all of the modules in our tests
either lack physical addresses or have them identical to virtual ones.
In the discussion on the patch, we came to the conclusion that in the
scenario where we are merely setting a load address of a module (for
example from a dynamic loader plugin), we should always use virtual
addresses (i.e., preserve status quo). This patch adds a test to make
sure we don't regress in that direction.
Differential Revision: https://reviews.llvm.org/D44738