Give more errors for specific failure conditions

Some failure conditions implicitly fail by failing some other check.
But the error messages are more helpful if they say explicitly what
actually caused the failure, so add those as failure conditions and
errors.

test/functional/rpc_deriveaddresses.py

@@ -13,14 +13,14 @@ class DeriveaddressesTest(BitcoinTestFramework):
         self.supports_cli = 1
 
     def run_test(self):
-        assert_raises_rpc_error(-5, "Invalid descriptor", self.nodes[0].deriveaddresses, "a")
+        assert_raises_rpc_error(-5, "Missing checksum", self.nodes[0].deriveaddresses, "a")
 
         descriptor = "wpkh(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/0)#t6wfjs64"
         address = "bcrt1qjqmxmkpmxt80xz4y3746zgt0q3u3ferr34acd5"
         assert_equal(self.nodes[0].deriveaddresses(descriptor), [address])
 
         descriptor = descriptor[:-9]
-        assert_raises_rpc_error(-5, "Invalid descriptor", self.nodes[0].deriveaddresses, descriptor)
+        assert_raises_rpc_error(-5, "Missing checksum", self.nodes[0].deriveaddresses, descriptor)
 
         descriptor_pubkey = "wpkh(tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1/1/0)#s9ga3alw"
         address = "bcrt1qjqmxmkpmxt80xz4y3746zgt0q3u3ferr34acd5"