perf: reduce use of starlark .split

[jbedard]

Changes are visible to end-users: no

Test plan

• Covered by existing test cases

[aspect-workflows]

Test

All tests were cache hits

194 tests (100.0%) were fully cached saving 37s.

---

Test

e2e/bzlmod

All tests were cache hits

4 tests (100.0%) were fully cached saving 459ms.

---

Test

e2e/gyp_no_install_script

All tests were cache hits

2 tests (100.0%) were fully cached saving 534ms.

---

Test

e2e/js_image_oci

All tests were cache hits

1 test (100.0%) was fully cached saving 7s.

---

Test

e2e/npm_link_package

All tests were cache hits

2 tests (100.0%) were fully cached saving 583ms.

---

Test

e2e/npm_link_package-esm

All tests were cache hits

2 tests (100.0%) were fully cached saving 1s.

---

Test

e2e/npm_translate_lock

All tests were cache hits

1 test (100.0%) was fully cached saving 73ms.

---

Test

e2e/npm_translate_lock_empty

All tests were cache hits

1 test (100.0%) was fully cached saving 73ms.

---

Test

e2e/npm_translate_lock_multi

All tests were cache hits

2 tests (100.0%) were fully cached saving 271ms.

---

Test

e2e/npm_translate_lock_partial_clone

All tests were cache hits

1 test (100.0%) was fully cached saving 117ms.

---

Test

e2e/npm_translate_lock_subdir_patch

All tests were cache hits

1 test (100.0%) was fully cached saving 269ms.

---

Test

e2e/npm_translate_package_lock

All tests were cache hits

1 test (100.0%) was fully cached saving 73ms.

---

Test

e2e/npm_translate_yarn_lock

All tests were cache hits

1 test (100.0%) was fully cached saving 73ms.

---

Test

e2e/package_json_module

All tests were cache hits

1 test (100.0%) was fully cached saving 574ms.

---

Test

e2e/pnpm_lockfiles

All tests were cache hits

28 tests (100.0%) were fully cached saving 13s.

---

Test

e2e/pnpm_workspace

All tests were cache hits

10 tests (100.0%) were fully cached saving 6s.

---

Test

e2e/pnpm_workspace_rerooted

All tests were cache hits

10 tests (100.0%) were fully cached saving 6s.

---

Test

e2e/repo_mapping

All tests were cache hits

2 tests (100.0%) were fully cached saving 464ms.

---

Test

e2e/rules_foo

All tests were cache hits

2 tests (100.0%) were fully cached saving 460ms.

---

Test

e2e/vendored_node

All tests were cache hits

1 test (100.0%) was fully cached saving 229ms.

---

Buildifier      Format