`AddressSize` parameter is not used by `DataExtractor` and will be
removed in the future. See #190519 for more context.
This also removes two of the four related methods:
```
DataExtractor::GetAsLLVM()
DataExtractor::GetAsLLVMDWARF() - removed as unused
DWARFDataExtractor::GetAsLLVM() - removed as redundant, it hid the equivalent method of DataExtractor
DWARFDataExtractor::GetAsLLVMDWARF()
```
That is, now we have:
```
DataExtractor::GetAsLLVM()
DWARFDataExtractor::GetAsLLVMDWARF()
```
6a02dc584b