[JITLink][PowerPC] Correct handling of R_PPC64_REL24_NOTOC

According to the ELFv2 ABI

> This relocation type is used to specify a function call where the TOC pointer is not initialized. It is similar to R_PPC64_REL24 in that it specifies a symbol to be resolved. If the symbol resolves to a function that requires a TOC pointer (as determined by st_other bits) then a link editor must arrange for the call to be via the global entry point of the called function. Any stub code must not rely on a valid TOC base address in r2.

This patch fixes handling of `R_PPC64_REL24_NOTOC` by using the same stub code sequence as lld.

Reviewed By: lhames

Differential Revision: https://reviews.llvm.org/D155672