[LLVM] Fix CodeGenLLVM::LinkParameters (#8213)
[LLVM] Fix CodeGenLLVM::LinkParameters (#8213)

- Generate valid LLVM IR.
- Set proper alignment on the constant variables.
dmlc/tvm,Laurawly/tvm-1,Laurawly/tvm-1,dmlc/tvm,dmlc/tvm,Laurawly/tvm-1,dmlc/tvm,Laurawly/tvm-1,dmlc/tvm,dmlc/tvm,dmlc/tvm,dmlc/tvm,Laurawly/tvm-1,Laurawly/tvm-1,Laurawly/tvm-1,Laurawly/tvm-1,dmlc/tvm,Laurawly/tvm-1,Laurawly/tvm-1