optimise statement insertion

src/Bundle.js

@@ -247,14 +247,23 @@ export default class Bundle {
 		// reinsert each statement, ensuring its strong dependencies appear first
 		let sorted = [];
 		let included = blank();
+		let highestIndex = blank();
 
 		function include ( statement ) {
 			if ( included[ statement.id ] ) return;
 			included[ statement.id ] = true;
 
+			let alreadyIncluded = false;
+
+			const unordered = statement.index < highestIndex[ statement.module.id ];
+			highestIndex[ statement.module.id ] = Math.max(
+				statement.index,
+				highestIndex[ statement.module.id ] || 0
+			);
+
+			if ( unordered ) {
 				const len = sorted.length;
 				let i = 0;
-			let alreadyIncluded = false;
 
 				for ( i = 0; i < len; i += 1 ) {
 					// ensure that this statement appears above later statements
@@ -263,11 +272,12 @@ export default class Bundle {
 					const existing = sorted[i];
 					if ( existing.module === statement.module && existing.index > statement.index ) {
 						sorted.splice( i, 0, statement );
-					alreadyIncluded = true;
+						return
+					}
 				}
 			}
 
-			if ( !alreadyIncluded ) sorted.push( statement );
+			sorted.push( statement );
 		}
 
 		this.statements.forEach( statement => {