This patch use the same way as the https://reviews.llvm.org/rGfe1fa43f16beac1506a2e73a9f7b3c81179744eb to handle the thread local variable.
It allocates 2 * pointerSize space in GOT to represent the thread key and data address. Instead of using the _tls_get_addr function, I customed a function __orc_rt_elfnix_tls_get_addr to get the address of thread local varible. Currently, this is a wip patch, only one TLS relocation R_X86_64_TLSGD is supported and I need to add the corresponding test cases.
To allocate the TLS descriptor in GOT, I need to get the edge kind information in PerGraphGOTAndPLTStubBuilder, So I add a `Edge::Kind K` argument in some functions in PerGraphGOTAndPLTStubBuilder.h. If it is not suitable, I can think further to solve this problem.