Enable analyses that do not require LTO

[DavidKorczynski]

LTO can be incompatible with certain projects, in particular larger projects. Both in terms of resource exhaustion and pure compatibility (i.e. breaking builds).

An option is to enable a mode of fuzz-introspector that does not rely on LTO, but provides analyses based on data that is not extracted with LTO. In essence, LTO is used to extract program-wide data, so, analyses without LTO should simply be based on data that is non-program-wide. This is e.g.

• function-level data
• runtime coverage data
• partial cfgs, e.g. (module) level data.

Ref google/oss-fuzz#7573 (comment)