[lldb] Make ObjectFileJSON loadable as a module

This patch adds support for creating modules from JSON object files.
This is necessary for the crashlog use case where we don't have either a
module or a symbol file. In that case the ObjectFileJSON serves as both.

The patch adds support for an object file type (i.e. executable, shared
library, etc). It also adds the ability to specify sections, which is
necessary in order specify symbols by address. Finally, this patch
improves error handling and fixes a bug where we wouldn't read more than
the initial 512 bytes in GetModuleSpecifications.

Differential revision: https://reviews.llvm.org/D148062