FIR: Fix codegen test data after safe-call refactoring

^KT-38444 In Progress

compiler/testData/codegen/box/classes/kt1247.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun f(a : Int?, b : Int.(Int)->Int) = a?.b(1)
 
 fun box(): String {

compiler/testData/codegen/box/classes/kt1918.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 class Bar {
 }