Add android_sdk_repo_host to build platform-tools&build-tools

The Android SDK has been built with Make up until now, monolithically,
then split up into several sdk-repo zip files for different purposes.
The Mac and Windows SDKs really only need to contain the platform-tools
and build-tools pieces, but due to this monolithic sdk zip, we had to
build the whole SDK first.

This adds an `android_sdk_repo_host` module that can build these
platform-tools and build-tools zips.

Bug: 187222815
Change-Id: I55809e1d7447dd65e22461f921b2b8abb6d5f822

android/module.go

@@ -2818,11 +2818,13 @@ func (m *moduleContext) PackageFile(installPath InstallPath, name string, srcPat
 }
 
 func (m *moduleContext) packageFile(fullInstallPath InstallPath, srcPath Path, executable bool) PackagingSpec {
+	licenseFiles := m.Module().EffectiveLicenseFiles()
 	spec := PackagingSpec{
-		relPathInPackage: Rel(m, fullInstallPath.PartitionDir(), fullInstallPath.String()),
-		srcPath:          srcPath,
-		symlinkTarget:    "",
-		executable:       executable,
+		relPathInPackage:      Rel(m, fullInstallPath.PartitionDir(), fullInstallPath.String()),
+		srcPath:               srcPath,
+		symlinkTarget:         "",
+		executable:            executable,
+		effectiveLicenseFiles: &licenseFiles,
 	}
 	m.packagingSpecs = append(m.packagingSpecs, spec)
 	return spec