[Debuginfo] Add MSVC Synthetic and Summary providers to LLDB
Adds handling for `tuple$<>`, `ref$<slice$2<>`, `ref$<str$>` and `enum2$<>`.
Also fixes a bug in MSVC vec/string handling where the script was unable to determine the element's type due to LLDB ignoring template arg debug information
<details>
<summary>Sample code</summary>
```rust
pub enum Number {
One = 57,
Two = 99,
}
#[repr(u8)]
pub enum Container {
First(u32),
Second { val: u64, val2: i8 },
Third,
}
...
let u8_val = b'a';
let float = 42.78000000000001;
let tuple = (u8_val, float);
let str_val = "eef";
let mut string = "freef".to_owned();
let mut_str = string.as_mut_str();
let array: [u8; 4] = [1, 2, 3, 4];
let ref_array = array.as_slice();
let mut array2: [u32; 4] = [1, 2, 3, 4];
let mut_array = array2.as_mut_slice();
let enum_val = Number::One;
let mut enum_val2 = Number::Two;
let sum_val = Container::First(15);
let sum_val_2 = Container::Second { val: 0, val2: 0 };
let sum_val_3 = Container::Third;
let non_zero = NonZeroU128::new(100).unwrap();
let large_discr = NonZeroU128::new(255);
```
</details>
Before:
After:
try-job: aarch64-apple
try-job: x86_64-msvc-1
try-job: i686-msvc-1
try-job: x86_64-mingw-1
try-job: i686-mingw
try-job: aarch64-gnu
This greatly reduces the number of places that actually use the `rustc_layout_scalar_valid_range_*` attributes down to just 3:
```
library/core\src\ptr\non_null.rs
68:#[rustc_layout_scalar_valid_range_start(1)]
library/core\src\num\niche_types.rs
19: #[rustc_layout_scalar_valid_range_start($low)]
20: #[rustc_layout_scalar_valid_range_end($high)]
```
Everything else -- PAL Nanoseconds, alloc's `Cap`, niched FDs, etc -- all just wrap those `niche_types` types.
