[clang-tidy] As a simple heuristic don't emit a swap fixit that would create
negative-sized memsets.

memset(x, -1, 0) is still useless but swapping makes no sense here. Just emit
a warning.

llvm-svn: 213157
GitOrigin-RevId: 806bcabcdafbb1deb8e3f1821d848f33f67a8dd5
2 files changed