Tests: update some backend tests on enum entries

The enumEntriesIntrinsicMultipleEnums.kt test was supposed to check that
JVM backend generates 3 `$EntriesIntrinsicMappings` classes: for X, for
Y, and for Z. Mappings classes are generated for enums without
`entries`, i.e. Kotlin enums compiled without `EnumEntries` language
feature, and Java enums. The test incorrectly _enabled_ the language
feature for X though, and `$EntriesIntrinsicMappings` for X was
generated anyway because of KT-61208.

To keep the original intention of the test, I'm disabling the language
feature for X, so that it will be considered as enum without `entries`.
KT-61208 will be fixed in a separate commit (with separate tests).

The boxInline and bytecodeText tests changed their meaning when language
feature EnumEntries started to be enabled by default, so those changes
are a continuation to ebd43fc8c0. The behavior did not change after
enabling the feature, once again because of KT-61208.

Also, remove obsolete error suppressions which are no longer needed
after 64c8ce18a0.

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

@@ -3,11 +3,8 @@
 // IGNORE_BACKEND: JS, JVM
 // WITH_STDLIB
 
-@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
-
 import kotlin.enums.*
 
-
 enum class EnumWithClash {
     values,
     entries,
@@ -21,4 +18,4 @@ fun box(): String {
     if (EnumWithClash.entries.toString() != "entries") return "FAIL 2"
     if (enumEntries<EnumWithClash>().toString() != "[values, entries, valueOf]") return "FAIL 3"
     return "OK"
-}
+}