[RuntimeDyld][ELF] Fixed relocations referencing undefined TLS symbols

The classification of TLS symbols in ELF was changed from ST_Data to
ST_Other in the following commit:
018a484c

RuntimeDyldELF::processRelocationRef() needs to be updated to also
handle ST_Other symbols so that it handles TLS relocations correctly.
The current tests did not fail because we have a shortcut for global
symbols that are already defined.

Differential Revision: https://reviews.llvm.org/D143568