[IR] dumpKotlinLike: add testdata for FIR tests

compiler/testData/ir/irText/expressions/stringComparisons.fir.kt.txt

@@ -0,0 +1,15 @@
+fun test1(a: String, b: String): Boolean {
+  return greater(arg0 = a.compareTo(other = b), arg1 = 0)
+}
+
+fun test2(a: String, b: String): Boolean {
+  return less(arg0 = a.compareTo(other = b), arg1 = 0)
+}
+
+fun test3(a: String, b: String): Boolean {
+  return greaterOrEqual(arg0 = a.compareTo(other = b), arg1 = 0)
+}
+
+fun test4(a: String, b: String): Boolean {
+  return lessOrEqual(arg0 = a.compareTo(other = b), arg1 = 0)
+}