[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/contracts/contractWithRefiedGeneric.fir.txt

@@ -0,0 +1,12 @@
+public final inline fun <reified T, reified U> cast(value: R|kotlin/Any?|, z: R|U|): R|T|
+    [R|Contract description]
+     <
+        Returns(WILDCARD) -> value is T
+    >
+
+
+public final inline fun <reified T> requireIsInstance(value: R|kotlin/Any?|): R|kotlin/Unit|
+    [R|Contract description]
+     <
+        Returns(WILDCARD) -> value is T
+    >