[Concurrency] fix symbol linkage of asyncHandler class methods.

Fixes a TBD verification error.

rdar://72329062

Author: eeckstein

lib/SILGen/SILGenFunction.cpp

@@ -555,7 +555,7 @@ void SILGenFunction::emitAsyncHandler(FuncDecl *fd) {
     SILLinkage::Hidden, name, bodyFnTy, F.getGenericEnvironment(),
     loc, F.isBare(), F.isTransparent(),
     F.isSerialized(), IsNotDynamic, ProfileCounter(), IsNotThunk,
-    F.getClassSubclassScope(), F.getInlineStrategy(), F.getEffectsKind());
+    SubclassScope::NotApplicable, F.getInlineStrategy(), F.getEffectsKind());
   bodyFn->setDebugScope(new (getModule()) SILDebugScope(loc, bodyFn));
 
   SILGenFunction(SGM, *bodyFn, fd).emitFunction(fd);

test/TBD/async-handler.swift

@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend -enable-experimental-concurrency -emit-ir -o/dev/null -parse-as-library -module-name test -validate-tbd-against-ir=all %s
+
+// REQUIRES: VENDOR=apple 
+// REQUIRES: concurrency
+
+open class TestClass {
+  @asyncHandler
+  internal func publicFunc() { }
+
+  @asyncHandler
+  internal func internalFunc() { }
+}
+
+@asyncHandler
+public func globalFunc() { }