[JVM IR] ForLoopsLowering: Keep IMPLICIT_NOTNULL type-casts in next()

and `componentN()` calls.

There were issues when we have iterables from Java where the element
type has "not null" type information.

compiler/testData/codegen/box/ranges/javaInterop/javaCollectionOfNotNullFromStdlib.kt

@@ -0,0 +1,22 @@
+// !LANGUAGE: +StrictJavaNullabilityAssertions
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND_FIR: JVM_IR
+// WITH_RUNTIME
+// FULL_JDK
+
+import kotlin.test.*
+
+fun box(): String {
+    val map = java.util.LinkedHashMap<Int, Int>()
+    map.put(3, 42)
+    map.put(14, -42)
+
+    // Even though the type parameters on `map` are not nullable, the `values` property is implemented in Java and therefore there is
+    // @EnhancedNullability on its type argument (Int).
+    val actualValues = mutableListOf<Int>()
+    for (v in map.values) {
+        actualValues += v
+    }
+    assertEquals(listOf(42, -42), actualValues)
+    return "OK"
+}