fix(utils): RuleTester: Only call afterAll if defined

[ArnaudBarre]

When using RuleTester outside of a test runner, if fails to instantiate due to ReferenceError: afterAll is not defined.
This PR make it possible to use TS ESLint RuleTester in simple node scripts.

[nx-cloud]

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✅ Successfully ran 43 targets

• Node 16.x - nx test @typescript-eslint/eslint-plugin-tslint
• Node 16.x - nx test @typescript-eslint/eslint-plugin
• Node 14.x - nx test @typescript-eslint/eslint-plugin-tslint
• Node 14.x - nx test @typescript-eslint/eslint-plugin
• Node 12.x - nx test @typescript-eslint/eslint-plugin-internal
• Node 12.x - nx test @typescript-eslint/eslint-plugin-tslint
• Node 12.x - nx test @typescript-eslint/eslint-plugin
• Node 12.x - nx test @typescript-eslint/eslint-plugin-tslint
• Node 12.x - nx test @typescript-eslint/eslint-plugin
• Node 12.x - nx run-many --target=typecheck --all --parallel
• Node 12.x - nx run-many --target=build --all --parallel --exclude website
• Node 14.x - nx test @typescript-eslint/parser
• Node 14.x - nx test @typescript-eslint/type-utils
• Node 16.x - nx test @typescript-eslint/parser
• Node 16.x - nx test @typescript-eslint/type-utils
• Node 14.x - nx test @typescript-eslint/utils
• Node 12.x - nx test @typescript-eslint/parser
• Node 12.x - nx test @typescript-eslint/type-utils
• Node 12.x - nx test @typescript-eslint/parser
• Node 12.x - nx test @typescript-eslint/type-utils
• Node 12.x - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 14.x - nx test @typescript-eslint/scope-manager
• Node 14.x - nx test @typescript-eslint/visitor-keys
• Node 16.x - nx test @typescript-eslint/utils
• Node 14.x - nx test @typescript-eslint/typescript-estree
• Node 14.x - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 12.x - nx test @typescript-eslint/utils
• Node 12.x - nx run-many --target=build --all --parallel --exclude website
• Node 12.x - nx test @typescript-eslint/utils
• Node 16.x - nx test @typescript-eslint/scope-manager
• Node 12.x - nx test @typescript-eslint/scope-manager
• Node 12.x - nx test @typescript-eslint/visitor-keys
• Node 16.x - nx test @typescript-eslint/visitor-keys
• Node 12.x - nx test @typescript-eslint/typescript-estree
• Node 16.x - nx test @typescript-eslint/typescript-estree
• Node 12.x - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 12.x - nx test @typescript-eslint/scope-manager
• Node 12.x - nx test @typescript-eslint/visitor-keys
• Node 16.x - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 12.x - nx test @typescript-eslint/typescript-estree
• Node 12.x - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 12.x - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 12.x - nx run-many --target=build --all --parallel --exclude website --exclude website

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[typescript-eslint]

Thanks for the PR, @ArnaudBarre!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[codecov]

Codecov Report

Merging #4656 (b1cd4be) into main (cf325ce) will decrease coverage by 2.47%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #4656      +/-   ##
==========================================
- Coverage   94.25%   91.77%   -2.48%     
==========================================
  Files         151      202      +51     
  Lines        7971     8819     +848     
  Branches     2573     2778     +205     
==========================================
+ Hits         7513     8094     +581     
- Misses        262      514     +252     
- Partials      196      211      +15     

Flag	Coverage Δ
unittest	91.77% <0.00%> (-2.48%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
packages/utils/src/eslint-utils/RuleTester.ts	11.36% <0.00%> (ø)
...plugin-internal/src/rules/prefer-ast-types-enum.ts	90.90% <0.00%> (ø)
packages/type-utils/src/getSourceFileOfNode.ts	0.00% <0.00%> (ø)
packages/type-utils/src/typeFlagUtils.ts	83.33% <0.00%> (ø)
packages/utils/src/eslint-utils/deepMerge.ts	89.47% <0.00%> (ø)
packages/utils/src/ts-eslint-scope/Reference.ts	100.00% <0.00%> (ø)
packages/type-utils/src/propertyTypes.ts	90.00% <0.00%> (ø)
packages/type-utils/src/getTokenAtPosition.ts	0.00% <0.00%> (ø)
packages/utils/src/eslint-utils/RuleCreator.ts	75.00% <0.00%> (ø)
packages/utils/src/ts-eslint-scope/Scope.ts	100.00% <0.00%> (ø)
... and 42 more

[bradzacher]

i don't see why not!
thanks for this!