feat: add polyfills insertion for ES Next used features

js/js.translator/testData/box/polyfills/clz32/clz32WithExistedIntrinsic.kt

@@ -0,0 +1,21 @@
+// WITH_STDLIB
+// TARGET_BACKEND: JS_IR
+// FILE: main.js
+Math.clz32 = function clz32(x) {
+    clz32.called = true;
+    var asUint = x >>> 0;
+    if (asUint === 0) {
+        return 32;
+    }
+    return 31 - (Math.log(asUint) / Math.LN2 | 0) | 0; // the "| 0" acts like math.floor
+}
+
+// FILE: main.kt
+fun box(): String {
+    val result = 4.countLeadingZeroBits()
+
+    assertEquals(result, 29)
+    assertEquals(js("Math.clz32.called"), true)
+
+    return "OK"
+}

js/js.translator/testData/box/polyfills/clz32/clz32WithoutExistedIntrinsic.kt

@@ -0,0 +1,14 @@
+// WITH_STDLIB
+// TARGET_BACKEND: JS_IR
+// FILE: main.js
+Math.clz32 = undefined;
+
+// FILE: main.kt
+fun box(): String {
+    val result = 4.countLeadingZeroBits()
+
+    assertEquals(result, 29)
+    assertEquals(js("Math.clz32.called"), js("undefined"))
+
+    return "OK"
+}