FIR: Unignore all Fir2IrText tests on context receivers

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

@@ -1,5 +1,4 @@
 // !LANGUAGE: +ContextReceivers
-// IGNORE_BACKEND_FIR: JVM_IR
 
 interface A {
     fun a(): Int
@@ -9,4 +8,4 @@ interface B {
 }
 
 context(A, B)
-val c get() = a() + b()
+val c get() = a() + b()