Test plan for "consumption of init-only properties"

[jcouv]

Main PR: #50414

Compiler:

• spec?
• language version (16 vs. 16.9)
• set from object creation initializer
• set inside constructor (versus some other method)
  • on Me, MyBase and MyClass
  • on some other instance
  • on conversions
• set from With expression
  • on Me, MyBase and MyClass
  • on some other instance
  • on conversions
• set on ByRef usage of property
• using init-only indexer (above permutations)
• in compound assignment
• from attribute usage
• override property
  • consume result from C#
• implement interface property
• decoding PE symbol from C#: modopt vs modreq, correct vs. incorrect attribute placement (on getter, other method, ...)
• late bound access (like dynamic)
• usage in synthesized code? (like foreach calls getter Current)
  • Dictionay member access Me!abc= value
  • ReDim
  • Erase
• symbol (.IsInitOnly), symbol display

Productivity:

• QuickInfo on VB usage (verified manually)
• GoToDev (verified manually)

Relates to C# feature: init-only setters