Add tests for converting license in androidmk

1. Added unit tests for license conversions in the androidmk tool, by
using a mocked filesystem;
2. Added integration tests in a shell script with a mocked filesystem.

Bug: 205615944
Test: m androidmk
Test: bash androidmk_test.sh
Test: TreeHugger
Change-Id: Id3d1f914190b52b82aadda7ea019192787b839d6
diff --git a/tests/run_integration_tests.sh b/tests/run_integration_tests.sh
index b19949a..76a918b 100755
--- a/tests/run_integration_tests.sh
+++ b/tests/run_integration_tests.sh
@@ -3,6 +3,7 @@
 set -o pipefail
 
 TOP="$(readlink -f "$(dirname "$0")"/../../..)"
+"$TOP/build/soong/tests/androidmk_test.sh"
 "$TOP/build/soong/tests/bootstrap_test.sh"
 "$TOP/build/soong/tests/mixed_mode_test.sh"
 "$TOP/build/soong/tests/bp2build_bazel_test.sh"