JVM IR: rename private fields for properties with same name

This is needed to get rid of the code that appends "$companion" to
properties moved from companion, because it caused inconsistencies in
the ABI and in JVM signatures stored in the metadata

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

@@ -16,14 +16,21 @@ public open class TestDelegate<T: Any>(private val initializer: () -> T) {
     }
 }
 
-class A {}
-class B {}
+class A
+class B
+class C
+class D
 
-public val A.s: String by TestDelegate( {"OK2"})
-public val B.s: String by TestDelegate( {"OK"})
+public val A.s: String by TestDelegate({"A"})
+public val B.s: String by TestDelegate({"B"})
+public val C.s: String by TestDelegate({"C"})
+public val D.s: String by TestDelegate({"D"})
 
 fun box() : String {
-  if (A().s != "OK2") return "fail1"
+    if (A().s != "A") return "Fail A"
+    if (B().s != "B") return "Fail B"
+    if (C().s != "C") return "Fail C"
+    if (D().s != "D") return "Fail D"
 
-  return B().s
+    return "OK"
 }

compiler/testData/codegen/box/fieldRename/jvmFieldNoClash1.kt

@@ -0,0 +1,23 @@
+// TARGET_BACKEND: JVM
+// WITH_RUNTIME
+
+// In the old JVM backend, FieldOwnerContext is sensitive to the order of properties which it invents name for. Companion object properties
+// are usually the first, so A.Companion.x here gets the name "x". After that it tries to invent a new name for A.x but fails because
+// @JvmField-annotated properties cannot be renamed, which leads to a JVM declaration clash error.
+// IGNORE_BACKEND: JVM
+
+class A {
+    @JvmField
+    val x = "outer"
+
+    companion object {
+        val x = "companion"
+    }
+}
+
+fun box(): String {
+    if (A().x != "outer") return "Fail outer"
+    if (A.x != "companion") return "Fail companion"
+
+    return "OK"
+}

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

@@ -0,0 +1,23 @@
+// TARGET_BACKEND: JVM
+// WITH_RUNTIME
+
+class A {
+    val x = "outer"
+    val y = "outer"
+
+    companion object {
+        @JvmField
+        val x = "companion"
+
+        const val y = "companion"
+    }
+}
+
+fun box(): String {
+    if (A().x != "outer") return "Fail outer x"
+    if (A().y != "outer") return "Fail outer y"
+    if (A.x != "companion") return "Fail companion x"
+    if (A.y != "companion") return "Fail companion y"
+
+    return "OK"
+}