testutil: remove unnecessary testutil.MockCmd.Restore()

While looking over the code I noticed that the `Restore()` helper
is not needed (and arguably wrong as it does not reset PATH).
We already use `t.TempDir()` and `t.Setenv()` as part of the
command setup so manually cleanup is not neccessary (and is today
even incomplete). So YAGNI and we can remove Restore().

internal/testutil/testutil.go

@@ -41,10 +41,6 @@ func (mc *MockCmd) Path() string {
 	return filepath.Join(mc.binDir, mc.name)
 }
 
-func (mc *MockCmd) Restore() error {
-	return os.RemoveAll(mc.binDir)
-}
-
 func (mc *MockCmd) Calls() [][]string {
 	b, err := os.ReadFile(mc.Path() + ".run")
 	if os.IsNotExist(err) {

internal/testutil/testutil_test.go

@@ -13,7 +13,6 @@ import (
 
 func TestMockCommand(t *testing.T) {
 	fakeCmd := testutil.MockCommand(t, "false", "exit 0")
-	defer fakeCmd.Restore()
 
 	err := exec.Command("false", "run1-arg1", "run1-arg2").Run()
 	assert.NoError(t, err)