Rework how JS's oo1.DB.exec() flags its Stmt objects to make certain Stmt APIs illegal (i.e. throwing) if called while that Stmt is being step()ped by DB.exec() (which can happen via client-provided per-result-row callbacks). This is an internal change only - the API is unaffected. Remove some unrelated dead code.

FossilOrigin-Name: 8c187140a60b62dc3b6066b8615766d52b7a29a5de992cbb6d312dbb225a980b

ext/wasm/tester1.c-pp.js

@@ -3323,6 +3323,44 @@ globalThis.sqlite3InitModule = sqlite3InitModule;
       db.close();
     })
 
+    /**
+       Ensure that certain Stmt members throw when called
+       via DB.exec().
+    */
+    .t('locked-by-exec() APIs', function(sqlite3){
+      const db = new sqlite3.oo1.DB();
+      db.exec("create table t(a);insert into t(a) values(1);");
+      let checkCount = 0;
+      const checkOp = function(op){
+        ++checkCount;
+        T.mustThrowMatching(() => {
+          db.exec({
+            sql: "select ?1",
+            bind: op,
+            callback: (row, stmt) => {
+              switch (row[0]) {
+                case 'bind': stmt.bind(1); break;
+                case 'finalize':
+                case 'clearBindings':
+                case 'reset':
+                case 'step': stmt[op](); break;
+              }
+            }
+          });
+        }, /^Operation is illegal when statement is locked.*/)
+      };
+      try{
+        checkOp('bind');
+        checkOp('finalize');
+        checkOp('clearBindings');
+        checkOp('reset');
+        checkOp('step');
+        T.assert(5===checkCount);
+      }finally{
+        db.close();
+      }
+    })
+
   ////////////////////////////////////////////////////////////////////
     .t("Misc. stmt_...", function(sqlite3){
       const db = new sqlite3.oo1.DB();