[addrman] inline Clear() into CAddrMan ctor

Clear() is now only called from the ctor, so just inline the code into
that function.

The LOCK(cs) can be removed, since there can be no data races in the ctor.

Also move the function definition out of the header and into the cpp file.

src/addrman.cpp

@@ -77,6 +77,32 @@ double CAddrInfo::GetChance(int64_t nNow) const
     return fChance;
 }
 
+CAddrMan::CAddrMan(bool deterministic, int32_t consistency_check_ratio)
+    : insecure_rand{deterministic}
+    , m_consistency_check_ratio{consistency_check_ratio}
+{
+    std::vector<int>().swap(vRandom);
+    nKey = insecure_rand.rand256();
+    for (size_t bucket = 0; bucket < ADDRMAN_NEW_BUCKET_COUNT; bucket++) {
+        for (size_t entry = 0; entry < ADDRMAN_BUCKET_SIZE; entry++) {
+            vvNew[bucket][entry] = -1;
+        }
+    }
+    for (size_t bucket = 0; bucket < ADDRMAN_TRIED_BUCKET_COUNT; bucket++) {
+        for (size_t entry = 0; entry < ADDRMAN_BUCKET_SIZE; entry++) {
+            vvTried[bucket][entry] = -1;
+        }
+    }
+
+    nIdCount = 0;
+    nTried = 0;
+    nNew = 0;
+    nLastGood = 1; //Initially at 1 so that "never" is strictly worse.
+    mapInfo.clear();
+    mapAddr.clear();
+    if (deterministic) nKey = uint256{1};
+}
+
 CAddrInfo* CAddrMan::Find(const CNetAddr& addr, int* pnId)
 {
     AssertLockHeld(cs);