FIR: Unignore all Fir2IrText tests on context receivers

compiler/testData/ir/irText/declarations/contextReceivers/overloading.kt

@@ -1,5 +1,4 @@
 // !LANGUAGE: +ContextReceivers
-// IGNORE_BACKEND_FIR: JVM_IR
 
 context(Int, String)
 fun foo(): Int {
@@ -15,4 +14,4 @@ fun test() {
     with(42) {
         foo()
     }
-}
+}