This commit adds a method `getDiagnosticsForComponent` to the
`TemplateTypeChecker`, which does the minimum amount of work to retrieve
diagnostics for a single component.
With the normal `ReusedProgramStrategy` this offers virtually no improvement
over the standard `getDiagnosticsForFile` operation, but if the
`TypeCheckingProgramStrategy` supports separate shims for each component,
this operation can yield a faster turnaround for components that are
declared in files with many other components.
PR Close#38105
d8c07b83c3