fix(minifier): preserve block statement in labeled iteration statements (#25162)

Preserve block statements inside labeled statements when they contain an
iteration statement (for/while/do-while).
Previously, these blocks were removed, which caused continue label
syntax errors to not be preserved in the minified output:

```js
label: {
  for (let i = 0; i < 10; i++) {
    continue label; // SyntaxError: 'label' does not denote an iteration statement
  }
}
```

fixes #25215

------------------

this guard is broad as we are not checking if inner loop has labeled
continue, this optimization could be implemented but its better if we
wait for #24155

```js
label: for (let i = 0; i < 10; i++) continue label;
```

crates/oxc_minifier/src/peephole/remove_dead_code.rs

@@ -43,6 +43,7 @@ impl<'a> PeepholeOptimizations {
                     || matches!(first, Statement::FunctionDeclaration(_))
                     || (matches!(first, Statement::IfStatement(decl) if decl.alternate.is_some())
                         && matches!(ctx.parent(), Ancestor::IfStatementConsequent(_)))
+                    || (first.is_iteration_statement() && ctx.parent().is_labeled_statement())
                 {
                     return;
                 }

crates/oxc_minifier/tests/peephole/minimize_exit_points.rs

@@ -12,8 +12,8 @@ fn test_break_optimization() {
     test("f:while(a())break f;", "f:for(;a();)break f;");
     test_same("f:for(x in a())break f");
 
-    test("f:{while(a())break;}", "f:for(;a();)break;");
-    test("f:{for(x in a())break}", "f:for(x in a())break;");
+    test("f:{while(a())break;}", "f:{for(;a();)break;}");
+    test("f:{for(x in a())break}", "f:{for(x in a())break;}");
 
     test("f:try{break f;}catch(e){break f;}", "f:try{break f}catch{break f}"); // ;
     test(
@@ -29,6 +29,30 @@ fn test_break_optimization() {
     test_same("function f() { a: { b(); return; } c(); }");
 }
 
+#[test]
+fn test_labeled_continue_optimization() {
+    test("a:while(true)continue a;", "a:for(;;)continue a;"); // a:for(;;);
+    test(
+        "x:while(x)y:while(y){if(a)continue x;if(b)continue x;}",
+        "x:for(;x;)y:for(;y;)if(a||b)continue x;",
+    );
+    test(
+        "x:while(x)y:while(y){if(a)continue y;if(b)continue y;}",
+        "x:for(;x;)y:for(;y;)if(a||b)continue y;",
+    ); // x:for(;x;)y:for(;y;)a||b;
+    test(
+        "x:while(x)y:while(y){if(a)continue x;if(b)continue y}",
+        "x:for(;x;)y:for(;y;){if(a)continue x;if(b)continue y}",
+    ); // x:for(;x;)y:for(;y;){if(a)continue x;b}
+    // SyntaxError: Illegal continue statement: 'a' does not denote an iteration statement
+    test_same("a:if(a()){b();continue a}");
+    // SyntaxError: Illegal continue statement: no surrounding iteration statement
+    test_same("a:{for(let i=0;i<10;i++)continue a}");
+    test("f:{if(true){a();continue f;}else;b();}", "f:{a();continue f}");
+    // SyntaxError: Undefined label 'a'
+    test_same("for(let i=0;i<10;i++)continue a;");
+}
+
 #[test]
 fn test_function_return_optimization() {
     test("function f(){return}", "function f(){}");