test(pycall): explicitly test that pycall is using the same python

Author: Christopher Doris

test/Compat.jl

@@ -42,6 +42,7 @@ end
     x1 = pylist()
     x2 = PyCall.PyObject(x1)
     x3 = Py(x2)
+    @test PythonCall.C.CTX.matches_pycall
     @test pyisinstance(x3, pybuiltins.list)
     @test pyis(x3, x1)
 end