Remove unnecessary TestMain()

Test: go test Soong tests
Change-Id: I2a8710361b1a32d71417b6c7bbc19e87fa8b36ae

apex/apex_test.go

@@ -16,7 +16,6 @@ package apex
 
 import (
 	"fmt"
-	"os"
 	"path"
 	"path/filepath"
 	"reflect"
@@ -9729,7 +9728,3 @@ func TestApexBuildsAgainstApiSurfaceStubLibraries(t *testing.T) {
 	libcCoreVariant := result.ModuleForTests("libc.apiimport", "android_arm64_armv8-a_shared").Module()
 	android.AssertBoolEquals(t, "core variant should link against source libc", true, hasDep(libfooCoreVariant, libcCoreVariant))
 }
-
-func TestMain(m *testing.M) {
-	os.Exit(m.Run())
-}