Previously, if a component had an external template with a hard error, the
compiler would "forget" the link between that component and its NgModule.
Additionally, the NgModule would be marked as being in error, because the
template issue would prevent the compiler from registering the component
class as a component, so from the NgModule it would look like a declaration
of a non-directive/pipe class. As a combined result, the next incremental
step could fix the template error, but would not refresh diagnostics for the
NgModule, leading to an incrementality issue.
The various facets of this problem were fixed in prior commits. This commit
adds a test verifying the above case works now as expected.
PR Close#39923