Move .java and .kotlin extension properties to kotlin.jvm

Delete the old ones in package kotlin.reflect.jvm because otherwise the code
using those functions will become red in a lot less meaningful way (overload
resolution ambiguity) than if they're deleted (unresolved import)

Based on the work originally done by @dnpetrov

 #KT-8380 Fixed

core/reflection.jvm/src/kotlin/reflect/jvm/_Deprecated.kt

@@ -45,3 +45,14 @@ public val <T> KClass<T>.declaredExtensionProperties: Collection<KProperty2<T, *
 public var KProperty<*>.accessible: Boolean
     get() = isAccessible
     set(value) { isAccessible = value }
+
+
+@deprecated("Use .java instead.", ReplaceWith("java"))
+public val <T> KClass<T>.__java: Class<T>
+    @jvmName("getJava")
+    get() = this.java
+
+@deprecated("Use .kotlin instead.", ReplaceWith("kotlin"))
+public val <T> Class<T>.__kotlin: KClass<T>
+    @jvmName("getKotlin")
+    get() = this.kotlin

core/reflection.jvm/src/kotlin/reflect/jvm/mapping.kt

@@ -17,19 +17,11 @@
 package kotlin.reflect.jvm
 
 import java.lang.reflect.*
-import kotlin.jvm.internal.Intrinsic
 import kotlin.reflect.*
 import kotlin.reflect.jvm.internal.*
 
 // Kotlin reflection -> Java reflection
 
-/**
- * Returns a Java [Class] instance corresponding to the given [KClass] instance.
- */
-@Intrinsic("kotlin.KClass.java.property")
-public val <T> KClass<T>.java: Class<T>
-    get() = (this as KClassImpl<T>).jClass
-
 /**
  * Returns a Java [Class] instance that represents a Kotlin package.
  * The methods and fields of this class are generated from top level functions and properties in the Kotlin package.
@@ -90,13 +82,6 @@ public val KType.javaType: Type
 
 // Java reflection -> Kotlin reflection
 
-// TODO: getstatic $kotlinClass or go to foreignKClasses
-/**
- * Returns a [KClass] instance corresponding to the given Java [Class] instance.
- */
-public val <T> Class<T>.kotlin: KClass<T>
-    get() = KClassImpl(this)
-
 /**
  * Returns a [KPackage] instance corresponding to the Java [Class] instance.
  * The given class is generated from top level functions and properties in the Kotlin package.