properly spill expressions with async function calls

src/analyze.cpp

@@ -5883,6 +5883,8 @@ static Error resolve_async_frame(CodeGen *g, ZigType *frame_type) {
         if (!fn_is_async(callee))
             continue;
 
+        mark_suspension_point(call->base.scope);
+
         call->frame_result_loc = ir_create_alloca(g, call->base.scope, call->base.source_node, fn,
                 callee_frame_type, "");
     }

test/stage1/behavior/async_fn.zig

@@ -1136,3 +1136,18 @@ test "await used in expression after a fn call" {
     };
     _ = async S.atest();
 }
+
+test "async fn call used in expression after a fn call" {
+    const S = struct {
+        fn atest() void {
+            var sum: i32 = 0;
+            sum = foo() + add(3, 4);
+            expect(sum == 8);
+        }
+        async fn add(a: i32, b: i32) i32 {
+            return a + b;
+        }
+        fn foo() i32 { return 1; }
+    };
+    _ = async S.atest();
+}