[arc] An apply of a callee_guaranteed thick function is a "guaranteed…

[gottesmm]

… use" of the function.

rdar://37820485
(cherry picked from commit 4941fba)

[gottesmm]

@swift-ci test

[swift-ci]

Build failed
Swift Test Linux Platform
Git Sha - c8567cf

[gottesmm]

The linux failure is due to git issue on the servers. Running again.

[gottesmm]

@swift-ci test linux platform

[swift-ci]

Build failed
Swift Test Linux Platform
Git Sha - c8567cf

[gottesmm]

@swift-ci test linux platform

[swift-ci]

Build failed
Swift Test Linux Platform
Git Sha - c8567cf

[gottesmm]

This passed testing, but the smoke test label builder didn't trigger appropriately.

[aschwaighofer]

LGTM

[gottesmm]

Explanation: When callee_guaranteed was enabled, the ARC optimizer was not taught that applying a callee_guaranteed thick function is a guaranteed use of the thick function. This PR fixes said issue.
Scope: This is an important change since not treating callee_guaranteed thick functions as guaranteed uses breaks ARC semantics and can cause use-after-free memory errors to occur.
Radar/SR Issue: SR-7064, rdar://37820485
Risk: Minimal. This is a small change that fixes an important correctness issue.
Testing: I wrote tests that test the specific pass in question and made sure that the behavior no longer showed up. I also ran the test app from SR-7064 with a modified compiler and verified that the app no longer crashes under guard malloc.
Reviewer: @aschwaighofer

[gottesmm]

@swift-ci test linux platform