CheckCompilerFlag: Add Swift Support
Plumb through Swift check_compiler_flag
support.
Add tests to check that valid flags work and invalid flags don't.
Follow up !7783 (merged).
Topic-rename: CheckCompilerFlag-Swift
Edited by Brad King
Plumb through Swift check_compiler_flag
support.
Add tests to check that valid flags work and invalid flags don't.
Follow up !7783 (merged).
Topic-rename: CheckCompilerFlag-Swift