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

compiler/testData/diagnostics/testsWithStdLib/purelyImplementedCollection/sets.fir.kt

@@ -0,0 +1,49 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+// !WITH_NEW_INFERENCE
+// FULL_JDK
+
+import java.util.*
+
+fun bar(): String? = null
+
+fun fooHashSet() {
+    var x = HashSet<String>()
+    x.add(null)
+    x.add(bar())
+    x.add("")
+
+    val b1: MutableSet<String?> = x
+    val b2: MutableSet<String> = x
+    val b3: Set<String?> = x
+
+    val b4: Collection<String?> = x
+    val b6: MutableCollection<String?> = x
+}
+
+fun fooTreeSet() {
+    var x = TreeSet<String>()
+    x.add(null)
+    x.add(bar())
+    x.add("")
+
+    val b1: MutableSet<String?> = x
+    val b2: MutableSet<String> = x
+    val b3: Set<String?> = x
+
+    val b4: Collection<String?> = x
+    val b6: MutableCollection<String?> = x
+}
+
+fun fooLinkedHashSet() {
+    var x = LinkedHashSet<String>()
+    x.add(null)
+    x.add(bar())
+    x.add("")
+
+    val b1: MutableSet<String?> = x
+    val b2: MutableSet<String> = x
+    val b3: Set<String?> = x
+
+    val b4: Collection<String?> = x
+    val b6: MutableCollection<String?> = x
+}