[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/dataFlow/assignment/assignToNewVal.fir.kt

@@ -0,0 +1,10 @@
+fun test(a: Any?) {
+    if (a == null) return
+    a.hashCode()
+
+    val b = a
+    b.hashCode()
+
+    val c: Any? = a
+    c.hashCode()
+}