fix: duplicate init typescriptLoader

[Vrainy]

This PR contains a:

• [x] bugfix
• [ ] new feature
• [ ] code refactor
• [ ] test update
• [ ] typo fix
• [ ] metadata update

Motivation / Use-Case

Breaking Changes

Additional Info

Each time the typescriptLoader is executed, ts-node will execute registerExtension() once.

Multiple executions of the typescriptLoader will get require.extensions[ext] = wrapper(wrapper(wrapper(wrapper(wrapper(... wrapper(originalHandler))))). ts-node source code

This will cause the out of memory when require.extensions[ext] is executed. #638

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