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/genericEntriesPropertyClashOn.kt

@@ -0,0 +1,18 @@
+// !LANGUAGE: +EnumEntries
+// WITH_STDLIB
+// FIR_DUMP
+
+package pckg
+
+enum class A {
+    ;
+
+    companion object
+}
+
+val <T> T.entries: Int get() = 0
+
+fun test() {
+    A.<!DEBUG_INFO_CALL("fqName: pckg.entries; typeCall: variable"), DEPRECATED_ACCESS_TO_ENUM_ENTRY_COMPANION_PROPERTY!>entries<!>
+    A.Companion.<!DEBUG_INFO_CALL("fqName: pckg.entries; typeCall: variable")!>entries<!>
+}