Simplify algorithm for opcode counting

Instead of explicitly counting all opcodes required while satisfaction,
we explicitly track only additional opcodes while satisfaction and
dissatisfaction.

Double-checked and compared with the c++ codebase

Author: sanket1729

src/miniscript/context.rs

@@ -381,7 +381,7 @@ impl ScriptContext for Legacy {
     fn check_local_consensus_validity<Pk: MiniscriptKey>(
         ms: &Miniscript<Pk, Self>,
     ) -> Result<(), ScriptContextError> {
-        match ms.ext.ops_count_sat {
+        match ms.ext.ops.op_count() {
             None => Err(ScriptContextError::MaxOpCountExceeded),
             Some(op_count) if op_count > MAX_OPS_PER_SCRIPT => {
                 Err(ScriptContextError::MaxOpCountExceeded)
@@ -494,7 +494,7 @@ impl ScriptContext for Segwitv0 {
     fn check_local_consensus_validity<Pk: MiniscriptKey>(
         ms: &Miniscript<Pk, Self>,
     ) -> Result<(), ScriptContextError> {
-        match ms.ext.ops_count_sat {
+        match ms.ext.ops.op_count() {
             None => Err(ScriptContextError::MaxOpCountExceeded),
             Some(op_count) if op_count > MAX_OPS_PER_SCRIPT => {
                 Err(ScriptContextError::MaxOpCountExceeded)
@@ -711,7 +711,7 @@ impl ScriptContext for BareCtx {
     fn check_local_consensus_validity<Pk: MiniscriptKey>(
         ms: &Miniscript<Pk, Self>,
     ) -> Result<(), ScriptContextError> {
-        match ms.ext.ops_count_sat {
+        match ms.ext.ops.op_count() {
             None => Err(ScriptContextError::MaxOpCountExceeded),
             Some(op_count) if op_count > MAX_OPS_PER_SCRIPT => {
                 Err(ScriptContextError::MaxOpCountExceeded)

src/miniscript/mod.rs

@@ -575,7 +575,7 @@ mod tests {
                 assert_eq!(format!("{:x}", ms.encode()), expected_hex);
                 assert_eq!(ms.ty.mall.non_malleable, non_mal);
                 assert_eq!(ms.ty.mall.safe, need_sig);
-                assert_eq!(ms.ext.ops_count_sat.unwrap(), ops);
+                assert_eq!(ms.ext.ops.op_count().unwrap(), ops);
             }
             (Err(_), false) => return,
             _ => unreachable!(),