p503: changes import paths

changes import path from github.com/cloudflare/p751sidh to
github.com/cloudflare/sidh

p503/arith_amd64.go

@@ -2,7 +2,7 @@
 
 package p503
 
-import cpu "github.com/cloudflare/p751sidh/internal/utils"
+import cpu "github.com/cloudflare/sidh/internal/utils"
 
 // There couple of reasons for having those variables here:
 // * to have an access to them from assembly

p751/arith_amd64.go

@@ -2,7 +2,7 @@
 
 package p751
 
-import cpu "github.com/cloudflare/p751sidh/internal/utils"
+import cpu "github.com/cloudflare/sidh/internal/utils"
 
 // There couple of reasons for having those variables here:
 // * to have an access to them from assembly

p751/arith_amd64_test.go

@@ -6,6 +6,7 @@ import (
 	. "github.com/cloudflare/sidh/internal/isogeny"
 	cpu "github.com/cloudflare/sidh/internal/utils"
 
+	"reflect"
 	"testing"
 	"testing/quick"
 )