[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/compiledKotlinWithStdlib/fromLoadJava/enum.fir.txt

@@ -0,0 +1,15 @@
+public final enum class Test : R|kotlin/Enum<test/Test>| {
+    private constructor(a: R|kotlin/Int|): R|test/Test|
+
+    public final static enum entry A: R|test/Test|
+    public final static enum entry B: R|test/Test|
+    public final static fun values(): R|kotlin/Array<test/Test>| {
+    }
+
+    public final static fun valueOf(value: R|kotlin/String|): R|test/Test| {
+    }
+
+    public final static val entries: R|kotlin/enums/EnumEntries<test/Test>|
+        public get(): R|kotlin/enums/EnumEntries<test/Test>|
+
+}