FIR2IR: handle unbound reference with adapted arguments

compiler/testData/codegen/box/callableReference/equality/coercionToUnit.kt

@@ -1,6 +1,5 @@
 // IGNORE_BACKEND: JS, JS_IR, NATIVE
 // IGNORE_BACKEND: JS_IR_ES6
-// IGNORE_BACKEND_FIR: JVM_IR
 // FILE: test.kt
 
 fun checkEqual(x: Any, y: Any) {

compiler/testData/codegen/box/callableReference/serializability/adaptedReferences.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 // WITH_REFLECT
 

compiler/testData/ir/irText/expressions/callableReferences/unboundMemberReferenceWithAdaptedArguments.fir.txt

@@ -66,6 +66,7 @@ FILE fqName:<root> fileName:/unboundMemberReferenceWithAdaptedArguments.kt
             VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:p1 index:1 type:kotlin.Int
             BLOCK_BODY
               CALL 'public open fun foo (vararg xs: kotlin.Int): kotlin.Int declared in <root>.A' type=kotlin.Int origin=null
+                $this: GET_VAR 'p0: <root>.A declared in <root>.testUnbound.foo' type=<root>.A origin=null
   FUN name:testBound visibility:public modality:FINAL <> (a:<root>.A) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:<root>.A
     BLOCK_BODY