K2: reproduce KT-57954 and reorganize tests around enum entries warnings

In particular, here we add FIR_DUMP to all enum entries tests with
some deprecation diagnostics and the feature on, and remove all txt-files

compiler/testData/diagnostics/tests/enum/entries/javaEnumEntriesAmbiguityOn.fir.txt

@@ -0,0 +1,6 @@
+FILE: test.kt
+    public final fun test(): R|kotlin/Unit| {
+        Q|JEnumEntry|.R|/JEnumEntry.entries|
+        Q|JEnumStaticField|.R|/JEnumStaticField.entries|
+        Q|JEnumField|::R|/JEnumField.entries|
+    }