Add test cases to `oxc_semantic` that check scope flag behavior.
Also contains these tweaks:
- fix: allow disabling `with_module` on `SourceType`
- refactor: move `SymbolTester` to a separate file
- chore: add `Expect` trait & implement it on `SymbolTester`
Fold constant addition expressions. Handles string concatenation and
addition, both with implicit casting.
For example,
```ts
let x = 1 + 1
let y = "hello " + "world"
```
now becomes
```ts
let x = 2
let y = "hello world"
```
## Extra Goodies
- test(minifier): add `test_snapshot` helper to perform snapshot tests
with `insta`
- up(hir): implement `std::ops::Add` for `NumericValue`
- up(span): impl `TryFrom<Cow<'_, &str>>` for `Atom`
Fixes 11 TS conformance tests and 18 babel tests.
Adds types to the symbol table functionally conformant to TS behavior
but symbol flags implemented slightly differently.
Symbol redeclaration check is also not entirely conformant but fixing
this seems like a separate PR.
For testing purposes - consistent-export-type was also implemented
(WIP).
