Allow do concurrent inside cuf kernel directive (#127693)
Allow do concurrent inside cuf kernel directive to avoid the following
Lowering error:
```
void {anonymous}::FirConverter::genFIR(const Fortran::parser::CUFKernelDoConstruct&): Assertion `bounds && "Expected bounds on the loop construct"' failed.
```
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Co-authored-by: Valentin Clement (バレンタイン クレメン) <clementval@gmail.com>
