[stdlib] Remove bootstrap implementation of enumEntriesIntrinsic

It should have been already implemented as intrinsic in all backends.

Do not test enumEntries intrinsic in the old JVM BE.

KT-53154

Co-authored-by: Alexander Udalov <alexander.udalov@jetbrains.com>

compiler/testData/codegen/box/enum/enumEntriesIntrinsicWithoutFeature.kt

@@ -1,5 +1,5 @@
 // !LANGUAGE: -EnumEntries
-// IGNORE_BACKEND: JS_IR, JS_IR_ES6, WASM
+// IGNORE_BACKEND: JS_IR, JS_IR_ES6, WASM, JVM
 // WITH_STDLIB
 
 import kotlin.enums.*