Add experimental flag to 2 more tests

Author: nickolas-pohilets

test/Concurrency/voucher_propagation.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %s -Xfrontend -disable-availability-checking -o %t/voucher_propagation
+// RUN: %target-build-swift %s -Xfrontend -disable-availability-checking -enable-experimental-feature IsolatedDeinit -o %t/voucher_propagation
 // RUN: %target-codesign %t/voucher_propagation
 // RUN: MallocStackLogging=1 %target-run %t/voucher_propagation
 

test/attr/global_actor.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -verify %s  -disable-availability-checking -package-name myPkg
+// RUN: %target-swift-frontend -typecheck -verify %s  -disable-availability-checking -package-name myPkg -enable-experimental-feature IsolatedDeinit
 // REQUIRES: concurrency
 
 actor SomeActor { }