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

compiler/testData/diagnostics/tests/generics/nullability/useAsReceiver.fir.kt

@@ -0,0 +1,27 @@
+// !WITH_NEW_INFERENCE
+// !DIAGNOSTICS: -UNUSED_EXPRESSION,-UNUSED_VARIABLE
+
+fun <T : CharSequence?> T.bar1() {}
+fun CharSequence?.bar2() {}
+
+fun <T : CharSequence> T.bar3() {}
+
+fun <T : String?> foo(x: T) {
+    x.length
+    x?.length
+
+    if (1 == 1) {
+        x!!.length
+    }
+
+
+    x.bar1()
+    x.bar2()
+
+    x?.bar1()
+    x?.bar2()
+
+    x.<!INAPPLICABLE_CANDIDATE!>bar3<!>()
+
+    x?.let { it.length }
+}