Log the command line to soong.log when soong_ui starts

Change-Id: Ie39333e4771cddf4c828d5e3474e2e43001db807
Test: manual
diff --git a/cmd/soong_ui/main.go b/cmd/soong_ui/main.go
index 682fb75..4097e8a 100644
--- a/cmd/soong_ui/main.go
+++ b/cmd/soong_ui/main.go
@@ -218,6 +218,11 @@
 
 	trace.SetOutput(filepath.Join(logsDir, c.logsPrefix+"build.trace"))
 
+	log.Verbose("Command Line: ")
+	for i, arg := range os.Args {
+		log.Verbosef("  [%d] %s", i, arg)
+	}
+
 	defer func() {
 		stat.Finish()
 		criticalPath.WriteToMetrics(met)