Malformed types in on-catch not handled according to spec.

[johnniwinther]

The correct semantics is

try {   throw 'foo'; } on Unresolved catch {   // Catch 'foo' in production mode.   // Throw type error in checked mode } catch {   // Never end here. }

See http://dartbug.com/8356

[iposva-google]

Removed Priority-Medium label. Added Priority-Unassigned label.

[iposva-google]

Set owner to @crelier. Removed Priority-Unassigned label. Added Priority-High, Accepted labels.

[crelier]

The VM implements the spec. No dynamic type error should be expected for a malformed type, either in production or checked mode, since the malformed type is mapped to dynamic.

See also 8356 and 7311.

---

Added Invalid label.