travis: enable test suite on ARM64 (#20219)

* travis: Enable ARM support

* Include fixes from 20039

* Add a trace to debug the invalid lookup issue

* Try increasing the timeout to see if the arm test passes

* Investigate the resolver issue

* Increase arm64 timeout for clique test

* increase timeout in tests for arm64

* Only test the failing tests

* Review feedback: don't export epsilon

* Remove investigation tricks+include fjl's feeback

* Revert the retry ahead of using the mock resolver

* Fix rebase errors

miner/worker_test.go

@@ -340,7 +340,9 @@ func testEmptyWork(t *testing.T, chainConfig *params.ChainConfig, engine consens
 		}
 	}
 	w.fullTaskHook = func() {
-		time.Sleep(100 * time.Millisecond)
+		// Aarch64 unit tests are running in a VM on travis, they must
+		// be given more time to execute.
+		time.Sleep(time.Second)
 	}
 
 	// Ensure worker has finished initialization
@@ -355,7 +357,7 @@ func testEmptyWork(t *testing.T, chainConfig *params.ChainConfig, engine consens
 	for i := 0; i < 2; i += 1 {
 		select {
 		case <-taskCh:
-		case <-time.NewTimer(2 * time.Second).C:
+		case <-time.NewTimer(4 * time.Second).C:
 			t.Error("new task timeout")
 		}
 	}