[NFC] Removed unused argument.

Previously getAsyncClosureEntryPointAndContextSize took both a pointer
for a function and a closure context.  That was a relic of a temporary
ABI where async function pointers were not used in all cases.  Now that
that ABI is long gone, async function pointers are always used.
Consequently, the closure context argument was unused.  Here, the
closure context argument is removed.

Author: nate-chandler

stdlib/public/Concurrency/Task.cpp

@@ -913,8 +913,7 @@ static AsyncTaskAndContext swift_task_create_commonImpl(
 template<typename AsyncSignature, uint16_t AuthDiscriminator>
 SWIFT_ALWAYS_INLINE // so this doesn't hang out as a ptrauth gadget
 std::pair<typename AsyncSignature::FunctionType *, size_t>
-getAsyncClosureEntryPointAndContextSize(void *function,
-                                        HeapObject *functionContext) {
+getAsyncClosureEntryPointAndContextSize(void *function) {
   auto fnPtr =
       reinterpret_cast<const AsyncFunctionPointer<AsyncSignature> *>(function);
 #if SWIFT_PTRAUTH
@@ -934,11 +933,10 @@ AsyncTaskAndContext swift::swift_task_create(
     void *closureEntry, HeapObject *closureContext) {
   FutureAsyncSignature::FunctionType *taskEntry;
   size_t initialContextSize;
-  std::tie(taskEntry, initialContextSize)
-    = getAsyncClosureEntryPointAndContextSize<
-      FutureAsyncSignature,
-      SpecialPointerAuthDiscriminators::AsyncFutureFunction
-    >(closureEntry, closureContext);
+  std::tie(taskEntry, initialContextSize) =
+      getAsyncClosureEntryPointAndContextSize<
+          FutureAsyncSignature,
+          SpecialPointerAuthDiscriminators::AsyncFutureFunction>(closureEntry);
 
   return swift_task_create_common(
       taskCreateFlags, options, futureResultType,