Use is instead of == for port equality

[leonardt]

== corresponds to instancing a mantle.EQ circuit for magma circuit ports. For the actions __eq__ method we want to check equality for testing purposes (e.g. compare a generated action sequence versus a manually crafted expected action sequence), so it should be using is instead of == to check object equality (versus just creating an EQ circuit).

[coveralls]

Pull Request Test Coverage Report for Build 848

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 77.822%

---

Totals
Change from base Build 840:	0.0%
Covered Lines:	1365
Relevant Lines:	1754

---

💛 - Coveralls