[JIT] Imbue stringbuf with C locale (#79929)
To prevent 12345 become "12,345" if locale is not "C", as shown in the
following example:
```cpp
int main() {
std::locale::global(std::locale("en_US.utf-8"));
std::stringstream ss;
ss << "12345 in " << std::locale().name() << " locale is " << 12345 ;
ss.imbue(std::locale("C"));
ss << " but in C locale is " << 12345;
std::cout << ss.str() << std::endl;
}
```
Fixes #79583
Pull Request resolved: https://github.com/pytorch/pytorch/pull/79929
Approved by: https://github.com/davidberard98
