test: Silence stderr output from test_obj_link_run.

test/standalone/test_obj_link_run/build.zig

@@ -26,6 +26,7 @@ pub fn build(b: *std.Build) void {
     b.default_step = test_step;
 
     const test_run = b.addRunArtifact(test_exe);
+    test_run.addCheck(.{ .expect_stderr_match = "All 3 tests passed." });
     test_step.dependOn(&test_run.step);
 }