[debugger] Enable side effects for frame evaluations
[debugger] Enable side effects for frame evaluations

Allow side effects for the expressions evaluated in the frame context: Watch
Window and Immediate Window.

This is implemented by allowing side effects for all "frame" evaluations.
Technically, we should do this only for the Immediate Window (and maybe
Watch Window), but this is basically the only case where frame
evaluations are used.

GitOrigin-RevId: 9ce05ec93ccf21e6ebf4a0152453c7c4c1711d8a

googlestadia/vsi-lldb,googlestadia/vsi-lldb,googlestadia/vsi-lldb