Don't make "in" parameters look like "out"/"in-out" parameters: pass by ref to const instead of ref to non-const

src/test/addrman_tests.cpp

@@ -71,7 +71,7 @@ public:
     }
 
     // Simulates connection failure so that we can test eviction of offline nodes
-    void SimConnFail(CService& addr)
+    void SimConnFail(const CService& addr)
     {
          LOCK(cs);
          int64_t nLastSuccess = 1;

src/test/net_tests.cpp

@@ -75,7 +75,7 @@ public:
     }
 };
 
-static CDataStream AddrmanToStream(CAddrManSerializationMock& _addrman)
+static CDataStream AddrmanToStream(const CAddrManSerializationMock& _addrman)
 {
     CDataStream ssPeersIn(SER_DISK, CLIENT_VERSION);
     ssPeersIn << Params().MessageStart();

src/test/util_tests.cpp

@@ -1860,7 +1860,7 @@ BOOST_AUTO_TEST_CASE(test_Capitalize)
     BOOST_CHECK_EQUAL(Capitalize("\x00\xfe\xff"), "\x00\xfe\xff");
 }
 
-static std::string SpanToStr(Span<const char>& span)
+static std::string SpanToStr(const Span<const char>& span)
 {
     return std::string(span.begin(), span.end());
 }