Rename soong_ui's upload-metrics-only mode.

It also processes bazel metrics, and is thus misnamed.

Bug: 279988780
Test: b build libcore:all (with prints to verify that it's called)
Change-Id: I99828e759872ba2dfb583c20a01b8101395b3558
diff --git a/cmd/soong_ui/main.go b/cmd/soong_ui/main.go
index 1c6aaad..eea41e6 100644
--- a/cmd/soong_ui/main.go
+++ b/cmd/soong_ui/main.go
@@ -92,13 +92,12 @@
 		stdio:       stdio,
 		run:         runMake,
 	}, {
-		flag:        "--upload-metrics-only",
-		description: "upload metrics without building anything",
+		flag:        "--finalize-bazel-metrics",
+		description: "finalize b metrics and upload",
 		config:      build.UploadOnlyConfig,
 		stdio:       stdio,
-		// Upload-only mode mostly skips to the metrics-uploading phase of soong_ui.
-		// However, this invocation marks the true "end of the build", and thus we
-		// need to update the total runtime of the build to include this upload step.
+		// Finalize-bazel-metrics mode updates metrics files and calls the metrics
+		// uploader. This marks the end of a b invocation.
 		run: finalizeBazelMetrics,
 	},
 }