Fix function/constructor/enum checks that relied on walking the "first declaration"

[jakebailey]

controlFlowFunctionLikeCircular1 was failing in concurrent checking for the same reasons we needed #2134.

This PR applies the same fix to the other places where we checked the "first declaration" of something in order to ensure it was only checked once.

Not 100% sure which links struct to use, so I let copilot choose. 😅

[Copilot]

Pull request overview

This PR updates the Go checker to avoid “check only on first declaration” patterns that break under concurrent checking, ensuring function/constructor/enum validation runs exactly once per symbol per checker (similar to the approach taken in #2134). It also re-enables the previously skipped concurrent-checking test case by accepting new baselines.

Changes:

• Replace “first declaration” gating for function/constructor checks with a per-checker ValueSymbolLinks guard (functionOrConstructorChecked).
• Replace “first declaration” gating for enum checks with a per-checker DeclaredTypeLinks guard (enumChecked).
• Unskip controlFlowFunctionLikeCircular1.ts and add/update baselines accordingly.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
internal/checker/checker.go	Removes first-declaration gating and introduces per-checker “checked once” guards for function/constructor symbols and enums.
internal/checker/types.go	Extends symbol link structs with new boolean guards used by the checker.
internal/testrunner/compiler_runner.go	Removes controlFlowFunctionLikeCircular1.ts from the concurrent-checking skip list.
testdata/baselines/reference/submodule/conformance/templateInsideCallback.errors.txt	Updates expected tsgo diagnostics output for the conformance/jsdoc test.
testdata/baselines/reference/submodule/conformance/templateInsideCallback.errors.txt.diff	Updates the tracked diff vs the TS submodule baseline (shows remaining divergence).
testdata/baselines/reference/submodule/compiler/controlFlowFunctionLikeCircular1.*	Adds/updates baselines now that the test is no longer skipped.

[Copilot]

The new TS2394 entry is marked with a leading '+' in this .diff baseline, which indicates tsgo is now emitting an extra diagnostic that the TypeScript submodule baseline does not. Please double-check upstream behavior for this test; if TS doesn’t report TS2394 here, this likely represents a regression (and the fix should avoid emitting it). If the mismatch is intentional/acceptable, consider moving this diff to the submoduleAccepted baselines so we’re explicitly tracking it as an accepted divergence.