[ELF] Restore arm-branch.s test
After D77330, the comments are inconsistent with the disassembled code.
As the value of far has been changed, a thunk to reach it is now
generated, and target addresses of branch instructions are different
from what was initially expected.
The patch fixes that and makes the test closer to what it was originally.
Differential Revision: https://reviews.llvm.org/D104286