JVM_IR: Lower IrGetEnumValue to this whenever possible.

The reference can be lowered to `this` if it is captured in the lexical
scope of the corresponding enum entry, and not used by the enum entry's
super constructor. Otherwise, it is lowered to
`GETFIELD SomeEnum.SomeEntry`.

compiler/testData/codegen/box/enum/deepInnerClassInEnumEntryClass.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-
 enum class A {
     X {
         val x = "OK"

compiler/testData/codegen/box/enum/deepInnerClassInEnumEntryClass2.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-
 enum class A {
     X {
         val k = "K"

compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor1.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 interface IFoo {
     fun foo(): String
 }

compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor2.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 interface IFoo {
     fun foo(): String
 }

compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor3.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 interface IFoo {
     fun foo(): String
 }

compiler/testData/codegen/box/enum/innerClassInEnumEntryClass.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-
 enum class A {
     X {
         val x = "OK"

compiler/testData/codegen/box/enum/innerClassMethodInEnumEntryClass.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-
 enum class A {
     X {
         val x = "OK"

compiler/testData/codegen/box/enum/kt20651.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 enum class Test(val x: String, val closure1: () -> String) {
     FOO("O", { FOO.x }) {
         override val y: String = "K"

compiler/testData/codegen/box/enum/kt20651_inlineLambda.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 enum class Test(val x: String, val closure1: () -> String) {
     FOO("O", run { { FOO.x } }) {
         override val y: String = "K"

compiler/testData/codegen/box/enum/kt7257.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 enum class X {
     B {
         val value2 = "K"

compiler/testData/codegen/box/enum/kt7257_anonObjectInit.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 enum class X {
     B {
         val value2 = "K"

compiler/testData/codegen/box/enum/kt7257_anonObjectMethod.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 enum class X {
     B {
         val value2 = "K"

compiler/testData/codegen/box/enum/kt7257_boundReference1.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-
 enum class X {
     B {
         val k = "K"

compiler/testData/codegen/box/enum/kt7257_boundReference2.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 enum class X {
     B {
 

compiler/testData/codegen/box/enum/kt7257_explicitReceiver.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 enum class X {
     B {
         override val value2 = "K"

compiler/testData/codegen/box/enum/kt7257_fullyQualifiedReceiver.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 enum class X {
     B {
         override val value2 = "K"

compiler/testData/codegen/box/enum/kt7257_namedLocalFun.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 enum class X {
     B {
         val value2 = "K"

compiler/testData/codegen/box/enum/kt7257_notInline.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 fun <T, R> T.letNoInline(fn: (T) -> R) =
         fn(this)