Don't blindly assume it is int.

In practice this is usually `unsigned` or `int`, so this commit should
not change behavior.

Also, remove scope of txnouttype in fuzz tests temporarily. The next
commit will add scopes to all txnouttype.

-BEGIN VERIFY SCRIPT-
 # General rename helper: $1 -> $2
 rename_global() { sed -i "s/\<$1\>/$2/g" $(git grep -l "$1"); }

 # Helper to rename TxoutType $1
 rename_value() {
   sed -i "s/    TX_$1,/    $1,/g" src/script/standard.h;  # First strip the prefix in the definition (header)
   rename_global TX_$1 "TxoutType::$1";                    # Then replace globally
 }

 # Change the type globally to bring it in line with the style-guide
 # (clsses are UpperCamelCase)
 rename_global 'enum txnouttype' 'enum class TxoutType'
 rename_global      'txnouttype'            'TxoutType'

 # Now rename each enum value
 rename_value 'NONSTANDARD'
 rename_value 'PUBKEY'
 rename_value 'PUBKEYHASH'
 rename_value 'SCRIPTHASH'
 rename_value 'MULTISIG'
 rename_value 'NULL_DATA'
 rename_value 'WITNESS_V0_KEYHASH'
 rename_value 'WITNESS_V0_SCRIPTHASH'
 rename_value 'WITNESS_UNKNOWN'

-END VERIFY SCRIPT-