FIR: Fix operator and infix flags for FIR builtins

compiler/testData/ir/irText/expressions/builtinOperators.kt

@@ -0,0 +1,12 @@
+// FIR_IDENTICAL
+// FILE: test.kt
+
+package test
+
+fun callBuiltinFunctions(a: Int, b: Int) {
+    a + b
+    a or b
+    a and b
+    a.inv()
+    a shl b
+}