Add --skip-soong-tests argument to soong_ui and use it in multiproduct_kati

There is no need for multiproduct_kati to run the tests for
every product, they don't vary by product config. --skip-soong-tests
can also be used for local development to run soong_build even if
the tests don't pass.

Bug: 156428456
Test: m --skip-soong-tests nothing
Change-Id: I9c00e3d1b6e51d17bb290339c3f124d4d1c9e69f
diff --git a/cmd/multiproduct_kati/main.go b/cmd/multiproduct_kati/main.go
index 7329aee..0a9b156 100644
--- a/cmd/multiproduct_kati/main.go
+++ b/cmd/multiproduct_kati/main.go
@@ -412,7 +412,9 @@
 	ctx.Status.AddOutput(terminal.NewStatusOutput(ctx.Writer, "", false,
 		build.OsEnvironment().IsEnvTrue("ANDROID_QUIET_BUILD")))
 
-	config := build.NewConfig(ctx, flag.Args()...)
+	args := append([]string(nil), flag.Args()...)
+	args = append(args, "--skip-soong-tests")
+	config := build.NewConfig(ctx, args...)
 	config.Environment().Set("OUT_DIR", outDir)
 	if !*keepArtifacts {
 		config.Environment().Set("EMPTY_NINJA_FILE", "true")