Merge bitcoin/bitcoin#21941: fuzz: Call const member functions in addrman fuzz test only once

faf7623 fuzz: Call const member functions in addrman fuzz test only once (MarcoFalke)

Pull request description:

  Logically based on #21940

  Currently the fuzz test may spend a long time generating random numbers:

  ![Screenshot from 2021-05-13 12-14-09](https://user-images.githubusercontent.com/6399679/118112238-06ecd880-b3e5-11eb-8013-6e0c20e6159f.png)

  Fix that by calling const member functions only once.

  Hopefully fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=34224

ACKs for top commit:
  practicalswift:
    cr ACK faf7623: touches only `src/test/fuzz/addrman.cpp`

Tree-SHA512: 0fe9e0111eb1706fc39bd2f90d4b87a771882bada54c01e96d8e79c2afca2f1081139d5ab680285a81835cc5142e74ada422a181db34b01904975d1e167e64c2

Author: MarcoFalke

src/test/fuzz/addrman.cpp

@@ -56,15 +56,6 @@ FUZZ_TARGET_INIT(addrman, initialize_addrman)
             [&] {
                 (void)addr_man.SelectTriedCollision();
             },
-            [&] {
-                (void)addr_man.Select(fuzzed_data_provider.ConsumeBool());
-            },
-            [&] {
-                (void)addr_man.GetAddr(
-                    /* max_addresses */ fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, 4096),
-                    /* max_pct */ fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, 4096),
-                    /* network */ std::nullopt);
-            },
             [&] {
                 const std::optional<CAddress> opt_address = ConsumeDeserializable<CAddress>(fuzzed_data_provider);
                 const std::optional<CNetAddr> opt_net_addr = ConsumeDeserializable<CNetAddr>(fuzzed_data_provider);
@@ -109,12 +100,16 @@ FUZZ_TARGET_INIT(addrman, initialize_addrman)
                 if (opt_service) {
                     addr_man.SetServices(*opt_service, ConsumeWeakEnum(fuzzed_data_provider, ALL_SERVICE_FLAGS));
                 }
-            },
-            [&] {
-                (void)addr_man.Check();
             });
     }
-    (void)addr_man.size();
+    const CAddrMan& const_addr_man{addr_man};
+    (void)/*const_*/addr_man.GetAddr(
+        /* max_addresses */ fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, 4096),
+        /* max_pct */ fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, 4096),
+        /* network */ std::nullopt);
+    (void)/*const_*/addr_man.Check();
+    (void)/*const_*/addr_man.Select(fuzzed_data_provider.ConsumeBool());
+    (void)const_addr_man.size();
     CDataStream data_stream(SER_NETWORK, PROTOCOL_VERSION);
-    data_stream << addr_man;
+    data_stream << const_addr_man;
 }