SI-8841 report named arg / assignment ambiguity also in silent mode.

For local definitions (eg. in a block that is an argument of a method
call), the type completer may have a silent context. A CyclicReference
is then not thrown but transformed into a NormalTypeError. When
deciding if 'x = e' is an assignment or a named arg, we need to report
cyclic references, but not other type errors. In the above case, the
cyclic reference was not reported.