net_processing: drop MaybePunishNodeForTx

Do not discourage nodes even when they send us consensus invalid
transactions.

Because we do not discourage nodes for transactions we consider
non-standard, we don't get any DoS protection from this check in
adversarial scenarios, so remove the check entirely both to simplify the
code and reduce the risk of splitting the network due to changes in tx
relay policy.

test/functional/data/invalid_txs.py

@@ -93,7 +93,7 @@ class BadTxTemplate:
 
 class OutputMissing(BadTxTemplate):
     reject_reason = "bad-txns-vout-empty"
-    expect_disconnect = True
+    expect_disconnect = False
 
     def get_tx(self):
         tx = CTransaction()
@@ -103,7 +103,7 @@ class OutputMissing(BadTxTemplate):
 
 class InputMissing(BadTxTemplate):
     reject_reason = "bad-txns-vin-empty"
-    expect_disconnect = True
+    expect_disconnect = False
 
     # We use a blank transaction here to make sure
     # it is interpreted as a non-witness transaction.
@@ -151,7 +151,7 @@ class BadInputOutpointIndex(BadTxTemplate):
 
 class DuplicateInput(BadTxTemplate):
     reject_reason = 'bad-txns-inputs-duplicate'
-    expect_disconnect = True
+    expect_disconnect = False
 
     def get_tx(self):
         tx = CTransaction()
@@ -163,7 +163,7 @@ class DuplicateInput(BadTxTemplate):
 
 class PrevoutNullInput(BadTxTemplate):
     reject_reason = 'bad-txns-prevout-null'
-    expect_disconnect = True
+    expect_disconnect = False
 
     def get_tx(self):
         tx = CTransaction()
@@ -189,7 +189,7 @@ class NonexistentInput(BadTxTemplate):
 
 class SpendTooMuch(BadTxTemplate):
     reject_reason = 'bad-txns-in-belowout'
-    expect_disconnect = True
+    expect_disconnect = False
 
     def get_tx(self):
         return create_tx_with_script(
@@ -198,7 +198,7 @@ class SpendTooMuch(BadTxTemplate):
 
 class CreateNegative(BadTxTemplate):
     reject_reason = 'bad-txns-vout-negative'
-    expect_disconnect = True
+    expect_disconnect = False
 
     def get_tx(self):
         return create_tx_with_script(self.spend_tx, 0, amount=-1)
@@ -206,7 +206,7 @@ class CreateNegative(BadTxTemplate):
 
 class CreateTooLarge(BadTxTemplate):
     reject_reason = 'bad-txns-vout-toolarge'
-    expect_disconnect = True
+    expect_disconnect = False
 
     def get_tx(self):
         return create_tx_with_script(self.spend_tx, 0, amount=MAX_MONEY + 1)
@@ -214,7 +214,7 @@ class CreateTooLarge(BadTxTemplate):
 
 class CreateSumTooLarge(BadTxTemplate):
     reject_reason = 'bad-txns-txouttotal-toolarge'
-    expect_disconnect = True
+    expect_disconnect = False
 
     def get_tx(self):
         tx = create_tx_with_script(self.spend_tx, 0, amount=MAX_MONEY)
@@ -224,7 +224,7 @@ class CreateSumTooLarge(BadTxTemplate):
 
 class InvalidOPIFConstruction(BadTxTemplate):
     reject_reason = "mandatory-script-verify-flag-failed (Invalid OP_IF construction)"
-    expect_disconnect = True
+    expect_disconnect = False
 
     def get_tx(self):
         return create_tx_with_script(
@@ -278,7 +278,7 @@ def getDisabledOpcodeTemplate(opcode):
 class NonStandardAndInvalid(BadTxTemplate):
     """A non-standard transaction which is also consensus-invalid should return the consensus error."""
     reject_reason = "mandatory-script-verify-flag-failed (OP_RETURN was encountered)"
-    expect_disconnect = True
+    expect_disconnect = False
     valid_in_block = False
 
     def get_tx(self):