all: don't rebind variables in for loops

See https://tip.golang.org/wiki/LoopvarExperiment#does-this-mean-i-dont-have-to-write-x--x-in-my-loops-anymore

Updates https://github.com/tailscale/tailscale/issues/11058

Signed-off-by: Alex Chan <alexc@tailscale.com>

tstest/archtest/qemu_test.go

@@ -33,7 +33,6 @@ func TestInQemu(t *testing.T) {
 	}
 	inCI := cibuild.On()
 	for _, arch := range arches {
-		arch := arch
 		t.Run(arch.Goarch, func(t *testing.T) {
 			t.Parallel()
 			qemuUser := "qemu-" + arch.Qarch

tstest/clock_test.go

@@ -56,7 +56,6 @@ func TestClockWithDefinedStartTime(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			clock := NewClock(ClockOpts{
@@ -118,7 +117,6 @@ func TestClockWithDefaultStartTime(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			clock := NewClock(ClockOpts{
@@ -277,7 +275,6 @@ func TestClockSetStep(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			clock := NewClock(ClockOpts{
@@ -426,7 +423,6 @@ func TestClockAdvance(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			clock := NewClock(ClockOpts{
@@ -876,7 +872,6 @@ func TestSingleTicker(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			var realTimeClockForTestClock tstime.Clock
@@ -1377,7 +1372,6 @@ func TestSingleTimer(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			var realTimeClockForTestClock tstime.Clock
@@ -1911,7 +1905,6 @@ func TestClockFollowRealTime(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			realTimeClock := NewClock(tt.realTimeClockOpts)
@@ -2364,7 +2357,6 @@ func TestAfterFunc(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			var realTimeClockForTestClock tstime.Clock
@@ -2468,7 +2460,6 @@ func TestSince(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			clock := NewClock(ClockOpts{

tstest/integration/integration_test.go

@@ -333,7 +333,6 @@ func TestOneNodeUpAuth(t *testing.T) {
 		tstest.Shard(t)
 
 		for _, useSeamlessKeyRenewal := range []bool{true, false} {
-			tt := tt // subtests are run in parallel, rebind tt
 			t.Run(fmt.Sprintf("%s-seamless-%t", tt.name, useSeamlessKeyRenewal), func(t *testing.T) {
 				tstest.Parallel(t)