perf: Improve type checking performance

[ghost]

Extends #10515

Summary
Visual Studio code intellicode lags due to the declared Schema Type
for testing the speed of the intellicode i used a simple typescript command as npm run tsc -- --extendedDiagnostics
Steps to reproduce

• clone the repository at : repro script
• run npm i
• then run npm run tsc -- --extendedDiagnostics
  Results (Before):
  
• apply the changes in the Pull Request
  Results (After):
  

This gives me back the snappy intellicode and also doesn't effect the types that much

Examples
Before applying the changes in the Pull Request.

indexjs-simplebot-visual-studio-code-2021-08-03-18-53-07-trim_IcxQNIcW_PNDt.mp4

After applying the changes in the Pull Request.

AFter.mp4

[andreialecu]

Note that this change breaks the types, some lines below become invalid/error out.

[vkarpov15]

We made these improvements along with the necessary patches to make our tests pass in fefebb3. Unfortunately this makes our type checking less strict, but the performance impact seems too good to pass up right now. Since our tests all pass, we don't think this change should be backwards breaking, but we'll keep an eye out for any bug reports.