[JVM_IR] Use direct field access to backing fields on current class.

The current backend uses direct field access to the backing field
instead of calling the companion object accessor, which calls
an accessibility bridge, which then gets the field for code such as:

```
class A {
  companion object {
    val s: String = "OK"
  }

  // f uses direct access to the A.s backing field.
  fun f() = s
}
```

This change does the same for the IR backend.

compiler/testData/codegen/box/companion/delegatedPropertyOnCompanion.kt

@@ -0,0 +1,46 @@
+import kotlin.reflect.KProperty
+
+class Delegate {
+    operator fun getValue(t: Any?, p: KProperty<*>): String = "OK"
+}
+
+class Delegate2 {
+    var value: String = "NOT OK"
+
+    operator fun getValue(t: Any?, p: KProperty<*>): String = value
+
+    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {
+        this.value = value
+    }
+}
+
+class A {
+    companion object {
+        val s: String by Delegate()
+        var s2: String by Delegate2()
+        var s3: String by Delegate2()
+    }
+
+    fun f() = s
+    inline fun g() = s
+
+    fun set2() {
+        s2 = "OK"
+    }
+    fun get2() = s2
+
+    inline fun set3() {
+        s3 = "OK"
+    }
+    inline fun get3() = s3
+}
+
+fun box(): String {
+    val a = A()
+    if (a.f() != "OK") return "FAIL0"
+    if (a.g() != "OK") return "FAIL0"
+    a.set2()
+    if (a.get2() != "OK") return "FAIL0"
+    a.set3()
+    return a.get3()
+}

compiler/testData/codegen/box/companion/inlineFunctionCompanionPropertyAccess.kt

@@ -0,0 +1,19 @@
+class A {
+    companion object {
+        val s = "OK"
+        var v = "NOT OK"
+    }
+
+    inline fun f(): String = s
+
+    inline fun g() {
+        v = "OK"
+    }
+}
+
+fun box(): String {
+    val a = A()
+    if (a.f() != "OK") return "FAIL0"
+    a.g()
+    return A.v
+}