Makefile: format C sources before generating Go
Makefile: format C sources before generating Go

If executor common headers are unformatted then go generate pkg/csource
will embed unformatted headers. Then format_cpp will re-format
only executor headers, but not embed versions. As the result
pkg/csource will end up with wrong embed headers.

Format C sources before generating Go to fix this.

google/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller