Dont pass -Zwrite-long-types-to-disk=no for ui-fulldeps --stage=1

src/tools/compiletest/src/runtest.rs

@@ -2330,7 +2330,14 @@ impl<'test> TestCx<'test> {
                 // Hide line numbers to reduce churn
                 rustc.arg("-Zui-testing");
                 rustc.arg("-Zdeduplicate-diagnostics=no");
-                rustc.arg("-Zwrite-long-types-to-disk=no");
+                // #[cfg(not(bootstrap)] unconditionally pass flag after beta bump
+                // since `ui-fulldeps --stage=1` builds using the stage 0 compiler,
+                // which doesn't have this flag.
+                if !(self.config.stage_id.starts_with("stage1-")
+                    && self.config.suite == "ui-fulldeps")
+                {
+                    rustc.arg("-Zwrite-long-types-to-disk=no");
+                }
                 // FIXME: use this for other modes too, for perf?
                 rustc.arg("-Cstrip=debuginfo");
             }