Partially reverting what has been removed in
https://github.com/facebook/react/pull/28186.
We need `'scheduler/tracing'` mock for React >= 16.8.
The error:
```
Invariant Violation: It is not supported to run the profiling version of a renderer (for example, `react-dom/profiling`) without also replacing the `scheduler/tracing` module with `scheduler/tracing-profiling`. Your bundler might have a setting for aliasing both modules. Learn more at http://fb.me/react-profiling
```
Validated by running regression tests for the whole version matrix:
```
./scripts/circleci/download_devtools_regression_build.js 16.0 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 16.0 --ci && ./scripts/circleci/download_devtools_regression_build.js 16.5 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 16.5 --ci && ./scripts/circleci/download_devtools_regression_build.js 16.8 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 16.8 --ci && ./scripts/circleci/download_devtools_regression_build.js 17.0 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 17.0 --ci && ./scripts/circleci/download_devtools_regression_build.js 18.0 --replaceBuild && node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 18.0 --ci
```
- Moving `act` implementation to a single getter-function, which is
based on React version we are testing RDT against.
- Removing unused mocks for `act`, which were designed for legacy
versions of React, validated with running tests against React 16 build.
Some older React versions have different module import names and are missing certain features. This PR mocks modules that don't exist and maps modules in older versions to the ones that are required in tests. Specifically:
* In React v16.5, scheduler is named schedule
* In pre concurrent React, there is no act
* Prior to React v18.0, react-dom/client doesn't exist
* In DevTools, we expect to use scheduler/tracing-profiling instead of scheduler/tracing
