[FIR-TEST] Move analysis tests to separate module

compiler/fir/analysis-tests/testData/resolve/smartcasts/controlStructures/elvis.kt

@@ -0,0 +1,17 @@
+// !DUMP_CFG
+interface A {
+    fun foo()
+    val b: Boolean
+}
+
+fun test_1(x: A?) {
+    if (x?.b ?: return) {
+        x.foo()
+    }
+}
+
+fun test2(a: Any?, b: Any?): String {
+    if (b !is String) return ""
+    if (a !is String?) return ""
+    return a ?: b
+}