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

compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/extensionReceiver.fir.kt

@@ -0,0 +1,38 @@
+// !LANGUAGE: +AllowContractsForCustomFunctions +UseReturnsEffect
+// !USE_EXPERIMENTAL: kotlin.contracts.ExperimentalContracts
+// !DIAGNOSTICS: -INVISIBLE_REFERENCE -INVISIBLE_MEMBER
+//
+// ISSUE: KT-28672
+
+import kotlin.contracts.*
+
+fun CharSequence?.isNullOrEmpty(): Boolean {
+    contract {
+        returns(false) implies (this@isNullOrEmpty != null)
+    }
+
+    return this == null || this.length == 0
+}
+
+fun smartcastOnReceiver(s: String?) {
+    with(s) {
+        if (isNullOrEmpty()) {
+            length
+        }
+        else {
+            length
+        }
+    }
+}
+
+fun mixedReceiver(s: String?) {
+    if (!s.isNullOrEmpty()) {
+        with(s) {
+            length
+        }
+    } else {
+        with(s) {
+            length
+        }
+    }
+}