[FIR-TEST] Move analysis tests to separate module

compiler/fir/analysis-tests/testData/resolve/stdlib/j+k/flexibleWildcard.kt

@@ -0,0 +1,13 @@
+// FILE: ContainerUtil.java
+import java.util.*;
+public class ContainerUtil {
+    public static <E> List<E> flatten(Iterable<? extends Collection<? extends E>> collections) {
+        return null;
+    }
+}
+// FILE: main.kt
+
+fun main(x: MutableCollection<Set<String>>) {
+    val y = ContainerUtil.flatten(x)
+    y[0].length
+}

compiler/fir/analysis-tests/testData/resolve/stdlib/j+k/flexibleWildcard.txt

@@ -0,0 +1,5 @@
+FILE: main.kt
+    public final fun main(x: R|kotlin/collections/MutableCollection<kotlin/collections/Set<kotlin/String>>|): R|kotlin/Unit| {
+        lval y: R|ft<kotlin/collections/MutableList<ft<kotlin/String, kotlin/String?>!>, kotlin/collections/List<ft<kotlin/String, kotlin/String?>!>?>!| = Q|ContainerUtil|.R|/ContainerUtil.flatten|<R|ft<kotlin/String, kotlin/String?>!|>(R|<local>/x|)
+        R|<local>/y|.R|FakeOverride<kotlin/collections/MutableList.get: R|ft<kotlin/String, kotlin/String?>!|>|(Int(0)).R|kotlin/String.length|
+    }