Migrate android package to a per test build directory

package android

import (

	"io/ioutil"

	"os"

	"testing"

)

var buildDir string

func setUp() {

	var err error

	buildDir, err = ioutil.TempDir("", "soong_android_test")

	if err != nil {

		panic(err)

	}

}

func tearDown() {

	os.RemoveAll(buildDir)

}

func TestMain(m *testing.M) {

	run := func() int {

		setUp()

		defer tearDown()

		return m.Run()

	}

	os.Exit(run())

	os.Exit(m.Run())

}

var emptyTestFixtureFactory = NewFixtureFactory(&buildDir)

var emptyTestFixtureFactory = NewFixtureFactory(nil)