[FixBug] Don't instantiate symbol for primitive functions

[hjjq]

Previously, if a primitive function calls a primitive function, the instantiate_symbols pass will update the corresponding hidet.ir.primitives.func.PrimitiveFunctionRegistry.function in-place (I am not sure exactly how it's done, but this is what I observed), adding symbol variables to its parameters. The primitive function pool is a global variable, therefore this effect is cumulative across tuning candidates. So while candidate 0 will have no problem, candidate 1 will have two extra copies of symbol params, and so on, leading to compile errors.

Since primitive functions do not need symbol vars, a quick fix is just to not instantiate any symbols for them.

[yaoyaoding]

Thanks @hjjq!