Use NodeIsMissing in typeeraser.go where Strada did

[jakebailey]

Fixes a few diffs. These are all in error cases, though.

[Copilot]

Pull request overview

This PR aligns the Go TypeScript transformer’s handling of “missing” function-like bodies with TypeScript’s behavior by using ast.NodeIsMissing (not just nil checks), eliminating several error-recovery emit mismatches and thereby reducing baseline diffs.

Changes:

• Update TypeEraserTransformer to treat empty-range (“missing”) bodies the same as nil bodies when deciding to elide overload-like declarations.
• Refresh affected reference baselines to reflect the corrected elision behavior (removing previously-emitted stub functions / adjusting emitted module markers).

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
internal/transformers/tstransforms/typeeraser.go	Uses ast.NodeIsMissing for constructor/method/function/accessor body checks so missing bodies created by error recovery don’t get emitted as empty stubs.
testdata/baselines/reference/submodule/conformance/typeGuardFunctionErrors.js.diff	Updates golden diff output after correcting erroneous stub emission.
testdata/baselines/reference/submodule/conformance/typeGuardFunctionErrors.js	Removes previously-emitted stub functions from the baseline output.
testdata/baselines/reference/submodule/conformance/thisTypeInFunctionsNegative.js.diff	Updates golden diff output after correcting erroneous stub emission.
testdata/baselines/reference/submodule/conformance/thisTypeInFunctionsNegative.js	Removes previously-emitted stub function from the baseline output.
testdata/baselines/reference/submodule/conformance/parserErrantEqualsGreaterThanAfterFunction2.js.diff	Updates golden diff output after correcting erroneous stub emission.
testdata/baselines/reference/submodule/conformance/parserErrantEqualsGreaterThanAfterFunction2.js	Removes previously-emitted stub function from the baseline output.
testdata/baselines/reference/submodule/conformance/jsdocDisallowedInTypescript.js.diff	Updates golden diff output after correcting erroneous stub emission.
testdata/baselines/reference/submodule/conformance/jsdocDisallowedInTypescript.js	Removes previously-emitted stub functions from the baseline output.
testdata/baselines/reference/submodule/compiler/reachabilityChecksNoCrash1.js.diff	Updates golden diff output after correcting erroneous stub emission and output shape.
testdata/baselines/reference/submodule/compiler/reachabilityChecksNoCrash1.js	Removes previously-emitted stub signature and restores/updates module marker emission (export {}) in baseline output.
testdata/baselines/reference/submodule/compiler/parseErrorIncorrectReturnToken.js.diff	Updates golden diff output after correcting erroneous stub emission.
testdata/baselines/reference/submodule/compiler/parseErrorIncorrectReturnToken.js	Removes previously-emitted object-literal stub from baseline output.
testdata/baselines/reference/submodule/compiler/dottedModuleName.js.diff	Updates golden diff output after correcting erroneous stub emission.
testdata/baselines/reference/submodule/compiler/dottedModuleName.js	Removes previously-emitted stub function assignment from baseline output.