Rename KClass.properties and extensionProperties: prepend 'member'

To better emphasize the fact that all returned properties require an instance
of the class they are declared in. Another issue was that
'Some::class.extensionProperties' was sometimes incorrectly perceived as
"get all extension properties available on the class Some"

compiler/testData/codegen/boxWithStdlib/reflection/properties/accessors/accessorNames.kt

@@ -22,7 +22,7 @@ fun box(): String {
     assertEquals("<get-baz>", A::baz.getter.name)
     assertEquals("<set-baz>", A::baz.setter.name)
 
-    val me = A::class.extensionProperties.single() as KMutableProperty2<A, String, String>
+    val me = A::class.memberExtensionProperties.single() as KMutableProperty2<A, String, String>
     assertEquals("<get-quux>", me.getter.name)
     assertEquals("<set-quux>", me.setter.name)
 

compiler/testData/codegen/boxWithStdlib/reflection/properties/accessors/memberExtensions.kt

@@ -8,7 +8,7 @@ class C(var state: String) {
 }
 
 fun box(): String {
-    val prop = C::class.extensionProperties.single() as KMutableProperty2<C, String, String>
+    val prop = C::class.memberExtensionProperties.single() as KMutableProperty2<C, String, String>
 
     val c = C("")
     assertEquals("3", prop.getter.invoke(c, "abc"))