Do not try to find PSI element, but always use the IR element offsets
instead. This greatly simplifies test data because we don't need to have
custom PSI- and LT- based diagnostic ranges in every test, and K1/K2
behavior also is mostly the same.
The exact offset ranges are not as important for backend diagnostics, so
it's better to have K2+PSI and K2+LT behaving the same.
Since SimpleDiagnosticsCollectorWithSuppress have been replaced by
PendingDiagnosticsCollectorWithSuppress after commit 9add6f3d55,
diagnostics need to be committed now.
#KT-54366 Fixed
Evgeniy.Zhelenskiy