Port some more truncation check related code

[jakebailey]

These are things I found while trying to work through #988.

[Copilot]

Pull Request Overview

Ports additional truncation-check features and refactors type-to-string logic, while updating submodule compiler snapshots.

• Refactors mapToTypeNodes to support truncation flags and adds corresponding truncation handling.
• Switches from typeToStringEx to a simpler typeToString helper and replaces visitedTypes map with collections.Set.
• Updates submodule compiler baselines for namespace disambiguation and computed-name declaration emit tests, and adds AST pooling for intersection-type nodes.

Reviewed Changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
internal/collections/multimap.go	Added Values() method to MultiMap
internal/checker/relater.go	Replaced typeToStringEx calls with typeToString
internal/checker/printer.go	Introduced typeToString helper and updated TypeToString
internal/checker/nodebuilderimpl.go	Refactored mapToTypeNodes, added truncation logic, changed visitedTypes type
internal/checker/nodebuilder.go	Removed visitedTypes map initialization
internal/ast/ast.go	Added pooling support for IntersectionTypeNode
testdata/baselines/reference/submodule/compiler/namespaceDisambiguationInUnion.errors.txt	Updated expected error messages
testdata/baselines/reference/submodule/compiler/declarationEmitSimpleComputedNames1.js	Fixed computed-names declaration emit baselines
testdata/baselines/reference/submodule/compiler/declarationEmitClassMemberWithComputedPropertyName.js	Adjusted computed-property declaration emit baselines

Comments suppressed due to low confidence (3)

internal/checker/nodebuilder.go:28

• The visitedTypes Set field is never initialized in enterContext, leading to nil-pointer panics when calling .Has or .Add. Initialize it, e.g., visitedTypes: collections.NewSet[TypeId](),.

		inferTypeParameters:      make([]*Type, 0),

internal/collections/multimap.go:63

• Consider adding unit tests for the new Values method to verify it returns the expected sequence of value slices.

func (s *MultiMap[K, V]) Values() iter.Seq[[]V] {

internal/checker/nodebuilderimpl.go:242

• Calling fmt.Sprintf here requires importing the fmt package. Add import "fmt" to the file's import block.

				text := fmt.Sprintf("... %d more ...", len(list)-2)