swift234

[frontend] Removed the separate TargetOptions class.

TargetOptions only contained the target triple, which was duplicated in
IRGenOptions. These could get out-of-sync, which would cause issues during
IRGen. Since nothing was using TargetOptions other than CompilerInvocation,
removed TargetOptions in favor of making IRGenOptions the canonical home of the
target triple.

Swift SVN r12869