Revert "Revert "ExecutionEngine: add R_AARCH64_ABS{16,32}""

This reverts commit SVN r313668.  The original test case attempted to
write a pointer value into 16-bits, although the value may exceed the
range representable in 16-bits.  Ensure that the symbol is located in
the address space such that its absolute address is representable in
16-bits.  This should fix the assertion failure that was seen on the
Windows hosts.

llvm-svn: 313822