Standardizes the is_xxx script function all take a script length, and changes
their first-level callers to pass it. This has several knock on benefits:
- We remove the repeated tal_count/tal_bytelen calls on the script, in
particular the redundant calls that result when we must check for multiple
types of script - which is almost all cases.
- We remove the dependency on the memory being tal-allocated (It is, in
all cases, but theres no reason we need to require that).
- We remove all cases where we create a copy of the script just to id it.
- We remove all allocations for non-interesting scripts while iterating block
txs in process_getfilteredblock_step1().
- We remove all allocations *including for potentially interesting scripts* in
topo_add_utxos().
Signed-off-by: Jon Griffiths <jon_p_griffiths@yahoo.com>