Concurrency: Remove currently-unused non-_f variants of swift_task_create

I'm about to replace these with new variations that correctly handle spawning a task with
a closure as its initial entry point, without leaking or requiring large amounts of caller-side
code generation.

Author: jckarter

include/swift/Runtime/Concurrency.h

@@ -30,21 +30,6 @@ struct AsyncTaskAndContext {
   AsyncContext *InitialContext;
 };
 
-/// Create a task object with no future which will run the given
-/// function.
-///
-/// The task is not yet scheduled.
-///
-/// If a parent task is provided, flags.task_hasChildFragment() must
-/// be true, and this must be called synchronously with the parent.
-/// The parent is responsible for creating a ChildTaskStatusRecord.
-/// TODO: should we have a single runtime function for creating a task
-///       and doing this child task status record management?
-SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
-AsyncTaskAndContext swift_task_create(JobFlags flags,
-                                      AsyncTask *parent,
-                const ThinNullaryAsyncSignature::FunctionPointer *function);
-
 /// Create a task object with no future which will run the given
 /// function.
 SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
@@ -58,24 +43,6 @@ AsyncTaskAndContext swift_task_create_f(JobFlags flags,
 using FutureAsyncSignature =
   AsyncSignature<void(void*), /*throws*/ true>;
 
-/// Create a task object with a future which will run the given
-/// function.
-///
-/// The task is not yet scheduled.
-///
-/// If a parent task is provided, flags.task_hasChildFragment() must
-/// be true, and this must be called synchronously with the parent.
-/// The parent is responsible for creating a ChildTaskStatusRecord.
-/// TODO: should we have a single runtime function for creating a task
-///       and doing this child task status record management?
-///
-/// flags.task_isFuture must be set. \c futureResultType is the type
-///
-SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
-AsyncTaskAndContext swift_task_create_future(
-    JobFlags flags, AsyncTask *parent, const Metadata *futureResultType,
-    const FutureAsyncSignature::FunctionPointer *function);
-
 /// Create a task object with a future which will run the given
 /// function.
 SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)

include/swift/Runtime/RuntimeFunctions.def

@@ -1502,7 +1502,7 @@ FUNCTION(TaskCancel,
          ARGS(SwiftTaskPtrTy),
          ATTRS(NoUnwind, ArgMemOnly))
 
-// AsyncTaskAndContext swift_task_create(
+// AsyncTaskAndContext swift_task_create_f(
 //     size_t flags, AsyncTask *task,
 //     TaskContinuationFunction* function,
 //     size_t contextSize);

stdlib/public/Concurrency/Task.cpp

@@ -212,13 +212,6 @@ static void completeTask(AsyncTask *task, ExecutorRef executor,
   swift_release(task);
 }
 
-AsyncTaskAndContext
-swift::swift_task_create(JobFlags flags, AsyncTask *parent,
-        const ThinNullaryAsyncSignature::FunctionPointer *function) {
-  return swift_task_create_f(flags, parent, function->Function.get(),
-                             function->ExpectedContextSize);
-}
-
 AsyncTaskAndContext
 swift::swift_task_create_f(JobFlags flags, AsyncTask *parent,
                 ThinNullaryAsyncSignature::FunctionType *function,
@@ -227,15 +220,6 @@ swift::swift_task_create_f(JobFlags flags, AsyncTask *parent,
       flags, parent, nullptr, function, initialContextSize);
 }
 
-AsyncTaskAndContext swift::swift_task_create_future(
-    JobFlags flags, AsyncTask *parent,
-    const Metadata *futureResultType,
-    const FutureAsyncSignature::FunctionPointer *function) {
-  return swift_task_create_future_f(
-      flags, parent, futureResultType, function->Function.get(),
-      function->ExpectedContextSize);
-}
-
 AsyncTaskAndContext swift::swift_task_create_future_f(
     JobFlags flags, AsyncTask *parent,
     const Metadata *futureResultType,