[FIR2IR] Add primitive signature composer & use it for external classes

compiler/testData/codegen/box/builtinStubMethods/Collection.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 
 class MyCollection<T>: Collection<T> {

compiler/testData/codegen/box/builtinStubMethods/immutableRemove.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // SKIP_JDK6
 // TARGET_BACKEND: JVM
 // FULL_JDK

compiler/testData/codegen/box/builtinStubMethods/nonTrivialSubstitution.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 
 class MyCollection<T> : Collection<List<Iterator<T>>> {

compiler/testData/codegen/box/collections/removeClash.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 class Queue<T>(override val size: Int) : Collection<T> {
     override fun contains(element: T): Boolean = TODO()
 

compiler/testData/codegen/box/collections/toArrayInJavaClass.kt

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

compiler/testData/codegen/box/inlineClasses/callSpeciallyOverriddenPropertyOfInlineClass.kt

@@ -1,5 +1,4 @@
 // !LANGUAGE: +InlineClasses
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 
 inline class UInt(val x: Int)

compiler/testData/codegen/box/specialBuiltins/redundantStubForSize.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 open class A1 {
     open val size: Int = 56
 }

compiler/testData/codegen/box/toArray/incorrectToArrayDetection.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // SKIP_JDK6
 // TARGET_BACKEND: JVM
 // FULL_JDK

compiler/testData/codegen/box/toArray/toArrayAlreadyPresent.kt

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

compiler/testData/ir/irText/classes/dataClassesGeneric.fir.txt

@@ -175,7 +175,7 @@ FILE fqName:<root> fileName:/dataClassesGeneric.kt
       $this: VALUE_PARAMETER GENERATED_DATA_CLASS_MEMBER name:<this> type:<root>.Test2<T of <root>.Test2>
       BLOCK_BODY
         RETURN type=kotlin.Nothing from='public open fun hashCode (): kotlin.Int declared in <root>.Test2'
-          CALL 'public open fun hashCode (): kotlin.Int declared in kotlin.Any' type=kotlin.Int origin=null
+          CALL 'public open fun hashCode (): kotlin.Int [fake_override] declared in kotlin.Number' type=kotlin.Int origin=null
             $this: GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:x type:T of <root>.Test2 visibility:private [final]' type=T of <root>.Test2 origin=null
               receiver: GET_VAR '<this>: <root>.Test2<T of <root>.Test2> declared in <root>.Test2.hashCode' type=<root>.Test2<T of <root>.Test2> origin=null
     FUN GENERATED_DATA_CLASS_MEMBER name:toString visibility:public modality:OPEN <> ($this:<root>.Test2<T of <root>.Test2>) returnType:kotlin.String