Re-port isUsedInFunctionOrInstanceProperty

[jakebailey]

Fixes #1870

[Copilot]

Pull Request Overview

This PR re-ports the isUsedInFunctionOrInstanceProperty function to fix issue #1870. The refactoring replaces a traditional for-loop traversal with the ast.FindAncestorOrQuit utility function for cleaner code structure and improved maintainability.

Key changes:

• Converted loop-based ancestor traversal to use ast.FindAncestorOrQuit pattern
• Updated return statements to use appropriate ast.FindAncestorResult values
• Added a test case to verify blocked scope variable behavior

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

File	Description
internal/checker/checker.go	Refactored isUsedInFunctionOrInstanceProperty to use ast.FindAncestorOrQuit instead of manual loop traversal
testdata/tests/cases/compiler/blockedScopeVariableNotUnused1.ts	Added test case for blocked scope variable usage validation
testdata/baselines/reference/compiler/blockedScopeVariableNotUnused1.*	Generated baseline files for the new test case

[DanielRosenwasser]

Nit on naming and comparison order to make it more readable

Suggested change

	initializerOfProperty := propertyDeclaration.Initializer() == current
	if initializerOfProperty {
	currentIsInitializer := current == propertyDeclaration.Initializer()
	if currentIsInitializer {

or if you flip the order, I'd argue you don't need a variable anyway

Suggested change

	initializerOfProperty := propertyDeclaration.Initializer() == current
	if initializerOfProperty {
	if current == propertyDeclaration.Initializer() {

[jakebailey]

This is 1:1 ported so I don't really want to futz with it.