Reinstate distributed actor typed throws test with proper availability

This test was failing in some configurations due to missing availability.
Address it in the same manner as other distributed tests do, by setting
a target triple with Swift 5.7.

Fixes rdar://144229403.

Author: DougGregor

test/Distributed/distributed_actor_typed_throws.swift

@@ -1,5 +1,5 @@
-// RUN: %target-typecheck-verify-swift
-// RUN: %target-swift-frontend -emit-sil -DMAKE_CORRECT %s -o - | %FileCheck %s
+// RUN: %target-swift-frontend -typecheck -verify -target %target-swift-5.7-abi-triple %s
+// RUN: %target-swift-frontend -emit-sil -target %target-swift-5.7-abi-triple -DMAKE_CORRECT %s -o - | %FileCheck %s
 
 // UNSUPPORTED: back_deploy_concurrency
 // REQUIRES: concurrency