[arm] Add big-endian version of pcrel fixups for adr instructions
    
    Summary:
    In 2e24219d3cbf, a number of ARM pcrel fixups were resolved at assembly
    time, to solve PR44929. This only covered little-endian ARM however, so
    add similar fixups for big-endian ARM. Also extend the test case to
    cover big-endian ARM.
    
    Reviewers: hans, psmith, MaskRay
    
    Reviewed By: psmith, MaskRay
    
    Subscribers: kristof.beyls, hiraditya, danielkiss, emaste, llvm-commits
    
    Tags: #llvm
    
    Differential Revision: https://reviews.llvm.org/D79774
    
    (cherry picked from commit fc373522b044e0b150561204958f0d603fb4caba)