JVM IR: slightly change field renaming convention implementation

Prefer to rename fields from the class, not from the companion, to be
more in line with the old backend's behavior. This has no effect on the
behavior of current tests but removes differences in metadata (since
metadata has information about every property->field mapping) in some of
them

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/RenameFieldsLowering.kt

@@ -48,9 +48,18 @@ private class RenameFieldsLowering(val context: CommonBackendContext) : FileLowe
 
             var count = 0
             // We never rename JvmField properties, since they are public ABI. Therefore we consider the JvmField-annotated property first,
-            // in order to make sure it'll claim its original name
-            // TODO: also do not rename const properties
-            for (field in fields.sortedByDescending { it.isJvmField }) {
+            // in order to make sure it'll claim its original name.
+            // If there are non-static and static (moved from companion) fields with the same name, we try to make static properties retain
+            // their original names first, since this is what the old JVM backend did. However this can easily be changed without any
+            // major binary compatibility consequences (modulo access to private members via Java reflection).
+            for (field in fields.sortedBy {
+                when {
+                    // TODO: also do not rename const properties
+                    it.isJvmField -> 0
+                    it.isStatic -> 1
+                    else -> 2
+                }
+            }) {
                 val oldName = field.name
                 val newName = if (count == 0) oldName else Name.identifier(oldName.asString() + "$$count")
                 count++

compiler/testData/codegen/box/fieldRename/jvmFieldNoClash2.kt

@@ -1,5 +1,8 @@
 // TARGET_BACKEND: JVM
 // WITH_RUNTIME
+// FULL_JDK
+
+import java.lang.reflect.Modifier
 
 class A {
     val x = "outer"
@@ -19,5 +22,11 @@ fun box(): String {
     if (A.x != "companion") return "Fail companion x"
     if (A.y != "companion") return "Fail companion y"
 
+    if (!Modifier.isStatic(A::class.java.getDeclaredField("x").modifiers))
+        return "Fail: A.x should be static"
+
+    if (Modifier.isStatic(A::class.java.getDeclaredField("x$1").modifiers))
+        return "Fail: A.x$1 should not be static"
+
     return "OK"
 }

compiler/testData/writeFlags/property/classObject/rename/delegatedAndDelegated.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 import kotlin.reflect.KProperty
 
 public open class TestDelegate<T: Any>(private val initializer: () -> T) {