Revert "core: Add a function check if a script is P2WSH without allocating"

The is_xxx script functions already perform these checks for us without
allocating. They currently expect their memory to be tal-allocated,
which is why a copy is made. However:

- The memory already *is* tal-allocated since wally is configured to do so.
- The tal-dependency is artifical and is removed in a future commit in
  this PR.

This reverts commit c329756723.

Signed-off-by: Jon Griffiths <jon_p_griffiths@yahoo.com>

bitcoin/script.c

@@ -10,6 +10,9 @@
 #include <common/utils.h>
 #include <sodium/randombytes.h>
 
+/* To push 0-75 bytes onto stack. */
+#define OP_PUSHBYTES(val) (val)
+
 /* Bitcoin's OP_HASH160 is RIPEMD(SHA256()) */
 static void hash160(struct ripemd160 *redeemhash, const void *mem, size_t len)
 {

bitcoin/script.h

@@ -13,9 +13,6 @@ struct ripemd160;
 struct rel_locktime;
 struct abs_locktime;
 
-/* To push 0-75 bytes onto stack. */
-#define OP_PUSHBYTES(val) (val)
-
 /* tal_count() gives the length of the script. */
 u8 *bitcoin_redeem_2of2(const tal_t *ctx,
 			const struct pubkey *key1,

bitcoin/tx.c

@@ -324,16 +324,6 @@ const u8 *bitcoin_tx_output_get_script(const tal_t *ctx,
 	return cln_wally_tx_output_get_script(ctx, output);
 }
 
-bool bitcoin_tx_output_script_is_p2wsh(const struct bitcoin_tx *tx, int outnum)
-{	const struct wally_tx_output *output;
-	assert(outnum < tx->wtx->num_outputs);
-	output = &tx->wtx->outputs[outnum];
-
-	return output->script_len == BITCOIN_SCRIPTPUBKEY_P2WSH_LEN &&
-	       output->script[0] == OP_0 &&
-	       output->script[1] == OP_PUSHBYTES(sizeof(struct sha256));
-}
-
 u8 *bitcoin_tx_output_get_witscript(const tal_t *ctx, const struct bitcoin_tx *tx,
 				    int outnum)
 {

bitcoin/tx.h

@@ -154,14 +154,6 @@ void bitcoin_tx_output_set_amount(struct bitcoin_tx *tx, int outnum,
  */
 const u8 *bitcoin_tx_output_get_script(const tal_t *ctx, const struct bitcoin_tx *tx, int outnum);
 
-/**
- * Return `true` if the given output is a P2WSH output.
- *
- * This is useful if you want to peek at the script, without having to
- * extract it first.
- */
-bool bitcoin_tx_output_script_is_p2wsh(const struct bitcoin_tx *tx, int outnum);
-
 /**
  * Helper to get the script of a script's output as a tal_arr
  *