With this change we reduce the amount of IO operations. This is especially a huge factor in windows since IO ops are slower.
With this change mainly we cache `existsSync` and `readFileSync` calls
Here's the results
Before
```
//packages/language-service/test:test
INFO: Elapsed time: 258.755s, Critical Path: 253.91s
```
After
```
//packages/language-service/test:test
INFO: Elapsed time: 66.403s, Critical Path: 63.13s
```
PR Close#30585
41cf066906