FIR: Unignore FIR2IR test

compiler/testData/codegen/box/binaryOp/kt23030_properIeee754comparisons.kt

@@ -1,5 +1,4 @@
 // !LANGUAGE: +ProperIeee754Comparisons
-// IGNORE_BACKEND_FIR: JVM_IR
 class C {
     operator fun Int.compareTo(c: Char) = 0
 
@@ -13,4 +12,4 @@ class C {
 
 fun box(): String {
     return C().foo(42, 'O')
-}
+}