[Mojo] Emit error when parametric function is passed as argument (#31044)

This is never legal, so the parser should catch it. The patch also
changes an assert in the parser that could get triggered if a parametric
function is passed as an argument: if the argument is called inside a
closure, the parser would crash because closure bodies are resolved even
if the parent function had a decl resolution error. From now on, this
assert will just turn into a suppressed error if and only if the a
parent func had a resolution error.

Closes [Internal Link]

modular-orig-commit: b1065e081f805239fb668ae014e46f86e71e7025

Author: laszlokindrat

docs/changelog.md

@@ -234,6 +234,8 @@ for x in v:
   [#1230](https://github.com/modularml/mojo/issues/1230),
   [#1699](https://github.com/modularml/mojo/issues/1699),
   [#1708](https://github.com/modularml/mojo/issues/1708)
+- [#1223](https://github.com/modularml/mojo/issues/1223) - Crash when parametric
+  function is passed as (runtime) argument. The parser now errors out instead.
 
 ## v0.7.0 (2024-01-25)