[FIR Test] Migrate AbstractFirLoadCompiledKotlin to new test infrastructure

Also introduce two different modes for those tests:
- load metadata compiled with K1
- load metadata compiled with K2

compiler/testData/loadJava/compiledKotlin/class/ClassMemberConflict.kt

@@ -1,4 +1,6 @@
 //ALLOW_AST_ACCESS
+// IGNORE_FIR_METADATA_LOADING_K2
+//   Ignore reason: KT-58028
 package test
 
 class ConstructorTypeParamClassObjectTypeConflict<test> {
@@ -42,4 +44,4 @@ class TestClassObjectAndClassConflict {
     val bla = { "More" }()
 
     val some = bla
-}
+}