JS: fixed <Type>Array.iterator methods; added -Xtypedarray compiler key

The <Type>Array.iterator used to lack next<Type>() method (KT-16626).

The -Xtypedarray compiler key enables translation of primitive arrays
to TypedArrays, and primitive array`is`-checks (KT-15358, KT-14007,
KT-14614, KT-16056).

compiler/testData/codegen/box/arrays/kt2997.kt

@@ -1,6 +1,6 @@
 //KT-2997 Automatically cast error (Array)
-// IGNORE_BACKEND: JS
-// Unmute when JS implements primitive arrays via TypeArray
+// IGNORE_BACKEND_WITHOUT_CHECK: JS
+// Unmute when JS implements primitive arrays via TypedArray
 
 fun foo(a: Any): Int {
     if (a is IntArray) {