[SR-5922] Fix-it for API availability inserts iOSApplicationExtension instead of iOS on frameworks

[NachoSoto]

Previous ID	SR-5922
Radar	rdar://problem/34519059
Original Reporter	@NachoSoto
Type	Bug

Environment

Swift version 4.0 (swiftlang-900.0.63 clang-900.0.37)

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, DiagnosticsQoI
Assignee	None
Priority	Medium

md5: e3ad821af15630b21949107e255f13e2

Issue Description:

On an iOS framework with a deployment target of iOS 10.0, the following code:

let view = UIStackView()
view.setCustomSpacing(0, after: UIView())

Produces:

'setCustomSpacing(_:after:)' is only available on iOS application extension 11.0 or newer
Add 'if #available' version check

With this fixit:

if #available(iOSApplicationExtension 11.0, *) {
  ...
}

However, that code ends up not being invoked, because the container is not an extension (in my particular project, this framework is used in an app AND an extension though, not sure if that's relevant).

[belkadan]

@devincoughlin, do you remember how we pick a platform for this?

@swift-ci create