[llvm] [llvm-jitlink] Fix detectStubKind() for big endian systems (PR #79970)

[Stefan Gränitz via llvm-commits]

weliveindetail wrote:

The issue was reported here: https://github.com/sx-aurora-dev/llvm-project/commit/e5ca202ef8870f3b46cc19a7a62624e6908be9a8#commitcomment-137959902

https://github.com/llvm/llvm-project/pull/79970