[JITlink][AArch32] Implement ELF::R_ARM_MOVT_ABS and R_ARM_MOVW_ABS_NC (#66219)

Add support for static Arm relocations of R_ARM_MOVT_ABS and R_ARM_MOVW_ABS_NC
which are emitted by movt and movw instructions. The implementation contains
relocation fixup and its testing as well as its encode/decode functions for
reading and writing immediate values together with its unittests.