Basic class members generation.

Split testData into 'classes' and 'expressions'.

compiler/testData/ir/irText/expressions/safeCallWithIncrementDecrement.kt

@@ -0,0 +1,20 @@
+package test
+
+class C
+
+var C?.p: Int
+    get() = 42
+    set(value) {}
+
+operator fun Int?.inc(): Int? = this?.inc()
+
+operator fun Int?.get(index: Int): Int = 42
+operator fun Int?.set(index: Int, value: Int) {}
+
+fun testProperty(nc: C?) {
+    nc?.p++
+}
+
+fun testArrayAccess(nc: C?) {
+    nc?.p[0]++
+}