[addrman] Ensure collisions eventually get resolved

After 40 minutes, time out a test-before-evict entry and just evict without
testing. Otherwise, if we were unable to test an entry for some reason, we
might break using feelers altogether.

src/addrman.h

@@ -166,6 +166,9 @@ public:
 //! the maximum number of tried addr collisions to store
 #define ADDRMAN_SET_TRIED_COLLISION_SIZE 10
 
+//! the maximum time we'll spend trying to resolve a tried table collision, in seconds
+static const int64_t ADDRMAN_TEST_WINDOW = 40*60; // 40 minutes
+
 /**
  * Stochastical (IP) address manager
  */