refactor: Apply consistent pattern for CAddrMan::Check usage

Co-authored-by: John Newbery <john@johnnewbery.com>

src/addrman.h

@@ -550,14 +550,11 @@ public:
 
     //! Randomly select an address in tried that another address is attempting to evict.
     CAddrInfo SelectTriedCollision()
-    {
-        CAddrInfo ret;
     {
         LOCK(cs);
         Check();
-            ret = SelectTriedCollision_();
+        const CAddrInfo ret = SelectTriedCollision_();
         Check();
-        }
         return ret;
     }
 
@@ -565,14 +562,11 @@ public:
      * Choose an address to connect to.
      */
     CAddrInfo Select(bool newOnly = false)
-    {
-        CAddrInfo addrRet;
     {
         LOCK(cs);
         Check();
-            addrRet = Select_(newOnly);
+        const CAddrInfo addrRet = Select_(newOnly);
         Check();
-        }
         return addrRet;
     }