L1I: Splitting function across generated binary

[ArsenyBochkarev]

We need to fuzz L1I caches by splitting basic blocks from it more or less evenly across the binary being generated. This can be achieved by using the HotColdSplitting pass unconditionally for as much BBs as possible

The effect we're trying to achieve here is something close to cache contention.

[ArsenyBochkarev]

I was able to utilize the HotColdSplitting pass for that purpose:

• I cut it and move the cut version into a separate pass called BasicBlocksExtraction
• In a new pass, single blocks are treated as separate regions
• All blocks are extracted in a separate sections with prefix __llvm_extracted

The test used for this pass: test.txt

Results with and without --fuzz=l1i option:

Fuzzed: fuzzed_res.txt

Nonfuzzed: nonfuzzed_res.txt