[Unity][UnitTest] Enable BindParams test for R.Prim (#15978)

This test was implemented in #15626,
but was initially disabled as it depended on functionality not
introduced until #15577.  Since that
PR has landed, cleaning up and enabling the unit test.

tests/python/relax/test_bind_params.py

@@ -111,21 +111,23 @@ def expected() -> R.Shape([16]):
 prim_value_dtype = tvm.testing.parameter("int64", "int32", "float32")
 
 
-@pytest.mark.xfail(reason="Depends on relax.PrimValue holding a tir.PrimExpr, PR#15577")
 def test_bind_prim_value(prim_value_dtype):
+    N = tir.Var("N", prim_value_dtype)
+    value = tir.const(16, prim_value_dtype)
+
     @R.function
-    def before(A: R.Prim(value="N", dtype=prim_value_dtype)):
+    def before(A: R.Prim(value=N)):
         R.func_attr({"global_symbol": "main"})
-        B: R.Prim(value="N", dtype=prim_value_dtype) = A
+        B: R.Prim(value=N) = A
         return B
 
     @R.function
-    def expected() -> R.Prim(value=16, dtype=prim_value_dtype):
+    def expected() -> R.Prim(value=value):
         R.func_attr({"global_symbol": "main"})
-        B = R.PrimValue(value=16, dtype=dtype)
+        B = R.prim_value(value)
         return B
 
-    after = before.bind_params({"A": relax.PrimValue(tir.const(16, prim_value_dtype))})
+    after = before.bind_params({"A": relax.PrimValue(value)})
 
     tvm.ir.assert_structural_equal(expected, after)