Unit tests for Calling extension methods on obsolete types and modules (#13297)

* Unit tests for Calling extension methods on obsolete types and modules

* Remove  Unexpected infix operator in definition

* Uopdate test to use withDiagnostics for more exhaustive error message checking

* Update tests/FSharp.Compiler.ComponentTests/Language/AttributeCheckingTests.fs

Co-authored-by: Petr Semkin <[email protected]>

* Update tests/FSharp.Compiler.ComponentTests/Language/AttributeCheckingTests.fs

Co-authored-by: Petr Semkin <[email protected]>

Co-authored-by: Petr Semkin <[email protected]>

Author: edgarfgp