test: prep manual equality assert conversions

The later scripted diff only handles plain `assert x == y` lines.
Some remaining tests still use equality inside comprehensions, parenthesized asserts, and other shapes that the line-based rewrite would misread.
Rewrite those sites by hand first so the later mechanical conversion stays safe.
The commit also simplifies the dead `len(["errors"]) == 0` branch in `blocktools.py`, which can never be true.

test/functional/wallet_conflicts.py

@@ -146,7 +146,8 @@ class TxConflicts(BitcoinTestFramework):
 
         unspents = alice.listunspent()
         assert_equal(len(unspents), 3)
-        assert all([tx["amount"] == 25 for tx in unspents])
+        for tx in unspents:
+            assert_equal(tx["amount"], 25)
 
         # tx1 spends unspent[0] and unspent[1]
         raw_tx = alice.createrawtransaction(inputs=[unspents[0], unspents[1]], outputs=[{bob.getnewaddress() : 49.9999}])
@@ -336,7 +337,8 @@ class TxConflicts(BitcoinTestFramework):
 
         unspents = alice.listunspent()
         assert_equal(len(unspents), 2)
-        assert all([tx["amount"] == 25 for tx in unspents])
+        for tx in unspents:
+            assert_equal(tx["amount"], 25)
 
         assert_equal(alice.getrawmempool(), [])