fixes

checked the actual dump which is different from Core's utxo dump. First coint has heightAndIsCoinbase = 0x81

0x80 is the same height with different isCoinbase
0x83 is a different height with same isCoinbase

Also the excessive amount test didn't work because the offset was wrong, see commit message bitcoin/bitcoin@e5ff4e4
> In addition, the undocumented offset is set surprisingly high (39 bytes is well into the
> serialization of the amount which starts at offset 36).
The values 39 and 36 are after core#29612 (Optimize dumptxoutset output), so they translate to 41 & 38 for us.

Author: PiRK

test/functional/feature_assumeutxo.py

@@ -125,36 +125,35 @@ def expected_error(log_msg="", rpc_details=""):
                 "3872c8e52554070ca410faff98e42f63c99d08f536be343af7c04143e0e8f2b2",
                 None,
             ],
-            # fIXME:
-            # # wrong coin code VARINT((coinbase ? 1 : 0) | (height << 1))
-            # [
-            #     b"\x81",
-            #     36,
-            #     "d631a0dbf1bba8536d1dd7aba0881a0ad83bdb4a8502f53fec8b89c549659633",
-            #     None,
-            # ],
-            # another wrong coin code
+            # wrong coin code VARINT((coinbase ? 1 : 0) | (height << 1))
+            # We expect b"\x81" (as seen in a dump of valid_snapshot_path)
             [
                 b"\x80",
                 36,
                 "b14c9595737179fe57e6d7a9f8e879a440833fa95ba52d210f1f7e3c02be64b2",
                 None,
             ],
+            # another wrong coin code
+            [
+                b"\x83",
+                36,
+                "296b4acd0d41dd4c0e845a7ed0cbdc602e5a7d092d5b4948a72835d2158f1e8e",
+                None,
+            ],
             # wrong coin case with height 364 and coinbase 0
             [
                 b"\x84\x58",
                 36,
                 None,
                 "[snapshot] bad snapshot data after deserializing 0 coins",
             ],
-            # FIXME: ???? does not trigger the correct error
-            # # Amount exceeds MAX_MONEY
-            # [
-            #     b"\xCA\xD2\x8F\x5A",
-            #     41,
-            #     None,
-            #     "[snapshot] bad snapshot data after deserializing 0 coins - bad tx out value",
-            # ],
+            # Amount exceeds MAX_MONEY
+            [
+                b"\xCA\xD2\x8F\x5A",
+                38,
+                None,
+                "[snapshot] bad snapshot data after deserializing 0 coins - bad tx out value",
+            ],
         ]
 
         for content, offset, wrong_hash, custom_message in cases: