[addrman] Add deterministic argument to CAddrMan ctor

Removes the need for tests to update nKey and insecure_rand after constructing
a CAddrMan.

src/test/fuzz/deserialize.cpp

@@ -188,7 +188,7 @@ FUZZ_TARGET_DESERIALIZE(blockmerkleroot, {
     BlockMerkleRoot(block, &mutated);
 })
 FUZZ_TARGET_DESERIALIZE(addrman_deserialize, {
-    CAddrMan am;
+    CAddrMan am(/* deterministic */ false);
     DeserializeFromFuzzingInput(buffer, am);
 })
 FUZZ_TARGET_DESERIALIZE(blockheader_deserialize, {