With clang 11 on macos we were getting this warning:
```
flang/runtime/random.cpp:61:30: error: non-constant-expression cannot be narrowed from type 'unsigned long long' to 'runtime::GeneratedWord' (aka 'unsigned int') in initializer list [-Wc++11-narrowing]
GeneratedWord word{(generator() - generator.min()) & rangeMask};
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
flang/runtime/random.cpp:99:5: note: in instantiation of function template specialization 'runtime::Generate<double, 53>' requested here
Generate<CppTypeFor<TypeCategory::Real, 8>, 53>(harvest);
^
```
Changing the type of `rangeMask` fixes it.
Differential Revision: https://reviews.llvm.org/D100320
Add APIs, initial non-coarray implementations, and unit
tests for the intrinsic subroutines for pseudo-random
number generation.
Differential Revision: https://reviews.llvm.org/D100064
Tim Keith