Not reflect true compile time per file

[a-vlad]

The flag used -debug-time-function-bodies only dumps function body times which can account for only a small subset of the total build time per file / for all swift files for some projects.

Would be better to add support for -debug-time-compilation flag which dumps total build time including its components on a per file basis.

Ref here for more flag info: https://bugs.swift.org/browse/SR-1788

Other option is use -driver-time-compilation recently added to fix above issue in this PR: swiftlang/swift#4367

[RobertGummesson]

Nice find, @a-vlad ! Will look into this. May need to get the standalone stuff working first though. Xcode 8 will soon be out of beta and I should have been further. :)

[taglia3]

+1