[lldb] Fix Scalar::GetData for non-multiple-of-8-bits values (#90846)

It was aligning the byte size down. Now it aligns up. This manifested
itself as SBTypeStaticField::GetConstantValue returning a zero-sized
value for `bool` fields (because clang represents bool as a 1-bit
value).

I've changed the code for float Scalars as well, although I'm not aware
of floating point values that are not multiples of 8 bits.