tests: Make msg_block a witness block #15982

Unnamed arguments are confusing as to what they mean without looking up
the function signature.

Since segwit is active by default in regtest, and all blocks are
serialized with witness (#15664, c459c5f), remove the argument
`with_witness=True` from all calls to `CBlock::serialize` and
`BlockTransactions::serialize`.

This diff has been created with a script, but is better reviewed without
a scripted diff.

sed -i --regexp-extended -e 's/block(_?[2a-z]*)\.serialize\([a-z_]*=?True/block\1.serialize(/g' $(git grep -l serialize ./test)

This diff has been generated with the following script, but is better
reviewed without looking at the script.

 # -BEGIN VERIFY SCRIPT-
echo "Use msg_witness_block everywhere, except for tests that require msg_block"
 # This could be a separate commit, but it is combined with the
 # following scripts to reduce the overall diff
sed -i -e 's/msg_block/msg_witness_block/g' ./test/functional/{feature_assumevalid,feature_cltv,feature_dersig,feature_versionbits_warning,p2p_fingerprint,p2p_sendheaders,p2p_unrequested_blocks,example_test,rpc_blockchain}.py

echo "Rename msg_block to msg_no_witness_block"
 # Rename msg_block to msg_no_witness_block in all tests (not the
 # framework)
sed -i -e 's/msg_block/msg_no_witness_block/g' $(git grep -l msg_block ./test/functional/*.py)
 # Derive msg_no_witness_block from msg_block
 # Make msg_block a witness block in messages.py
patch -p1 --fuzz 0 << EOF
diff --git a/test/functional/test_framework/messages.py b/test/functional/test_framework/messages.py
index 00190e4cbd..e454ed5987 100755
--- a/test/functional/test_framework/messages.py
+++ b/test/functional/test_framework/messages.py
@@ -1133 +1133 @@ class msg_block:
-        return self.block.serialize(with_witness=False)
+        return self.block.serialize()
@@ -1155 +1155 @@ class msg_generic:
-class msg_witness_block(msg_block):
+class msg_no_witness_block(msg_block):
@@ -1158,2 +1158 @@ class msg_witness_block(msg_block):
-        r = self.block.serialize()
-        return r
+        return self.block.serialize(with_witness=False)
@@ -1445 +1444 @@ class msg_blocktxn:
-        r += self.block_transactions.serialize(with_witness=False)
+        r += self.block_transactions.serialize()
@@ -1452 +1451 @@ class msg_blocktxn:
-class msg_witness_blocktxn(msg_blocktxn):
+class msg_no_witness_blocktxn(msg_blocktxn):
@@ -1456,3 +1455 @@ class msg_witness_blocktxn(msg_blocktxn):
-        r = b""
-        r += self.block_transactions.serialize()
-        return r
+        return self.block_transactions.serialize(with_witness=False)
EOF
 # Conclude rename of msg_block to msg_no_witness_block
sed -i -e 's/msg_witness_block/msg_block/g' $(git grep -l msg_witness_block)
 # -END VERIFY SCRIPT-