Remove the hooking for swift_task_getCurrent().

This is very performance-sensitive and unreasonable to change.

Author: rjmccall

stdlib/public/CompatibilityOverride/CompatibilityOverrideConcurrency.def

@@ -78,10 +78,6 @@ OVERRIDE_ACTOR(job_run, void,
                swift::, (class Job *job, ExecutorRef executor),
                (job, executor))
 
-OVERRIDE_ACTOR(task_getCurrent, AsyncTask *,
-               SWIFT_EXPORT_FROM(swift_Concurrency), SWIFT_CC(swift),
-               swift::, ,)
-
 OVERRIDE_ACTOR(task_getCurrentExecutor, ExecutorRef,
                SWIFT_EXPORT_FROM(swift_Concurrency), SWIFT_CC(swift),
                swift::, ,)

stdlib/public/Concurrency/Actor.cpp

@@ -245,7 +245,7 @@ void swift::runJobInEstablishedExecutorContext(Job *job) {
 }
 
 SWIFT_CC(swift)
-static AsyncTask *swift_task_getCurrentImpl() {
+AsyncTask *swift::swift_task_getCurrent() {
   return ActiveTask::get();
 }
 

unittests/runtime/CompatibilityOverrideConcurrency.cpp

@@ -116,10 +116,6 @@ TEST_F(CompatibilityOverrideConcurrencyTest, test_swift_job_run) {
   swift_job_run(nullptr, ExecutorRef::generic());
 }
 
-TEST_F(CompatibilityOverrideConcurrencyTest, test_swift_task_getCurrent) {
-  swift_task_getCurrent();
-}
-
 TEST_F(CompatibilityOverrideConcurrencyTest, test_swift_task_getCurrentExecutor) {
   swift_task_getCurrentExecutor();
 }