Rollup merge of #133590 - nnethercote:rename-parse-only, r=estebank

Rename `-Zparse-only`

It's a misleading name.

r? ````@estebank````

compiler/rustc_driver_impl/src/lib.rs

@@ -418,7 +418,9 @@ fn run_compiler(
                 return early_exit();
             }
 
-            if sess.opts.unstable_opts.parse_only || sess.opts.unstable_opts.show_span.is_some() {
+            if sess.opts.unstable_opts.parse_crate_root_only
+                || sess.opts.unstable_opts.show_span.is_some()
+            {
                 return early_exit();
             }