Migrate android package to a per test build directory

Bug: 182885307
Test: m nothing
Change-Id: I6b868bacc36be1f6768fbb2fb1d7ed4ad6e4118c

android/android_test.go

@@ -15,34 +15,12 @@
 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)