Limit the number of outstanding DNS queries by UID

Test: system/netd/tests/runtests.sh
Test: run netdutils_test on marlin:
    [----------] 3 tests from OperationLimiter
    [ RUN      ] OperationLimiter.limits
    [       OK ] OperationLimiter.limits (0 ms)
    [ RUN      ] OperationLimiter.finishWithoutStart
    [       OK ] OperationLimiter.finishWithoutStart (3 ms)
    [ RUN      ] OperationLimiter.destroyWithActiveOperations
    [       OK ] OperationLimiter.destroyWithActiveOperations (1 ms)
    [----------] 3 tests from OperationLimiter (6 ms total)
Bug: 79674503
Change-Id: I5f11f0ed6b6f2479921d90a919d17dfd7b7f5788
diff --git a/tests/dns_tls_test.cpp b/tests/dns_tls_test.cpp
index 7820338..bb5bfe5 100644
--- a/tests/dns_tls_test.cpp
+++ b/tests/dns_tls_test.cpp
@@ -135,7 +135,7 @@
     bool query(uint16_t id, const Slice query) override {
         // Return the response immediately (asynchronously).
         std::thread(&IDnsTlsSocketObserver::onResponse, mObserver, make_echo(id, query)).detach();
-	return true;
+        return true;
     }
 private:
     IDnsTlsSocketObserver* const mObserver;