Fix mining to an invalid target + ensure that a new block has the

correct hash internally in Python tests

Author: TheQuantumPhysicist

test/functional/feature_block.py

@@ -632,7 +632,7 @@ def run_test(self):
         self.move_tip(44)
         b47 = self.next_block(47, solve=False)
         target = uint256_from_compact(b47.nBits)
-        while b47.sha256 < target:
+        while b47.sha256 <= target:
             b47.nNonce += 1
             b47.rehash()
         self.send_blocks([b47], False, force_send=True, reject_reason='high-hash', reconnect=True)
@@ -1345,6 +1345,8 @@ def next_block(self, number, spend=None, additional_coinbase_value=0, script=CSc
             block.hashMerkleRoot = block.calc_merkle_root()
         if solve:
             block.solve()
+        else:
+            block.rehash()
         self.tip = block
         self.block_heights[block.sha256] = height
         assert number not in self.blocks