Discard function alignment padding from gap functions

[ahomescu]

MSVC on Windows prepends padding instructions to functions for alignment (it currently uses the CC opcode for this and a 16-byte alignment for all functions by default). We currently preserve those instructions as "gap functions", but they should be safe to discard. We could add a pass that scans all gap functions and trims them by removing all CC (and even 90 as well) opcode.