go.tools/pointer: fix pointer tests (fix build partly)

R=adonovan
CC=golang-dev
https://golang.org/cl/13246052

pointer/testdata/func.go

@@ -68,6 +68,7 @@ func swap(x, y *int) (*int, *int) { // @line swap
 func func4() {
 	a := make([]int, 10) // @line func4make
 	i, j := 123, 456     // @line f4j
+	_ = i
 	p, q := swap(&a[3], &j)
 	print(p) // @pointsto j@f4j:5
 	print(q) // @pointsto makeslice[*]@func4make:11
@@ -123,7 +124,7 @@ func func6() {
 	print(f()) // @pointsto main.a
 }
 
-// @calls main.func6 -> func@120.7
+// @calls main.func6 -> func@121.7
 
 type I interface {
 	f()

pointer/testdata/interfaces.go

@@ -78,7 +78,7 @@ func interface3() {
 	// There should be no backflow of concrete types from the type-switch to x.
 	var x interface{} = 0
 	print(x) // @types int
-	switch y := x.(type) {
+	switch x.(type) {
 	case int:
 	case string:
 	}

pointer/testdata/maps.go

@@ -31,7 +31,7 @@ func maps1() {
 
 	// Lookup doesn't create any aliases.
 	print(m2[&c]) // @pointsto main.a
-	if m2v, ok := m2[&a]; ok {
+	if _, ok := m2[&a]; ok {
 		print(m2[&c]) // @pointsto main.a
 	}
 }
@@ -39,7 +39,7 @@ func maps1() {
 func maps2() {
 	m1 := map[*int]*int{&a: &b}
 	m2 := map[*int]*int{&b: &c}
-	m3 := []map[*int]*int{m1, m2} // (no spurious merging of m1, m2)
+	_ = []map[*int]*int{m1, m2} // (no spurious merging of m1, m2)
 
 	print(m1[nil]) // @pointsto main.b
 	print(m2[nil]) // @pointsto main.c