This adds a size command to llvm-remarkutil.
llvm-remarkutil size --parser=<bitstream|yaml> <file>
This will, for now, only print out asm-printer InstructionCount remarks.
Frequently I need to find out things like "what are the top 10 largest functions" in a given project.
This makes it so we can find that information quickly and easily from any format of remarks.
I chose a CSV because I usually want to stick these into a spreadsheet, and the data is two-dimensional.
In the future, we may want to change this to another format if we add more complicated data.