Variable Breakpoints: Wrong Icon in gutter

[MarcusDenker]

Describe the bug
When adding a breakpoint for a variable, the icon is wrong

To Reproduce
Steps to reproduce the behavior:

1. select some ivar use in a method
2. menu, Debugging, "break on read to var"
3. See Metalink icon at the right, not the icon for breakpoints

Expected behavior
We should get only a Breakpoint icon

We did fix this for "normal" breakpoint. There the reason was that in #install, we were adding the metalink
before adding the breakpoint to the #breakpoints annotation on the AST node.

If we check the situation here, this is not possible as the link only knows after it has places where it will be placed

First thing to check: does #hasBreakpoint return true after adding the breakpoint to the variable?