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

compiler/testData/diagnostics/tests/smartCasts/safecalls/insideCall.fir.kt

@@ -0,0 +1,8 @@
+fun foo(y: Int): Int {
+    return y + 1
+}
+
+fun calc(x: List<String>?): Int {
+    // x should be non-null in arguments list
+    return foo(x?.get(x.size - 1)!!.length)
+}