Properly link properties and their getter/setters.

This allows removing a hack in the MethodSignatureMapper.

When introducing non-getter methods that dispatch to a getter
we have to be careful to use the right name.

DeepCopyIrTreeWithSymbols should create the link between new
properties and their new getter/setter.

compiler/testData/codegen/bytecodeText/builtinFunctions/size.kt

@@ -53,10 +53,6 @@ fun box(
     c2.size
 }
 
-/*
-
-*/
-
 // 8 public final bridge size\(\)I
 // 8 INVOKEVIRTUAL A[0-9]+\.size \(\)I
 // 1 INVOKEINTERFACE A9+\.size \(\)I