FIR: Update integer literal-related tests

They started failing once we began reporting diagnostics from completion

^KT-46419 Relates

compiler/testData/codegen/box/unaryOp/call.kt

@@ -1,3 +1,5 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+
 fun box(): String {
     val a1: Byte = 1.unaryMinus()
     val a2: Short = 1.unaryMinus()
@@ -14,4 +16,4 @@ fun box(): String {
     if (a6 != -1f) return "fail 6"
 
     return "OK"
-}
+}

compiler/testData/codegen/box/unaryOp/callNullable.kt

@@ -1,3 +1,5 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+
 fun box(): String {
     val a1: Byte? = 1.unaryMinus()
     val a2: Short? = 1.unaryMinus()

compiler/testData/codegen/box/unaryOp/longOverflow.kt

@@ -1,5 +1,7 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+
 fun box(): String {
     val a: Long = -(1 shl 31)
     if (a != -2147483648L) return "fail: in this case we should add to ints and than cast the result to long - overflow expected"
     return "OK"
-}
+}