Avoid hanging on takeHeaders (incorrect 103 handling) when response body is empty. (#7954) (#8054)

(cherry picked from commit 7308264)

Author: yschimke

okhttp/src/main/kotlin/okhttp3/internal/http2/Http2Stream.kt

@@ -258,12 +258,12 @@ class Http2Stream internal constructor(
       if (this.errorCode != null) {
         return false
       }
-      if (source.finished && sink.finished) {
-        return false
-      }
       this.errorCode = errorCode
       this.errorException = errorException
       notifyAll()
+      if (source.finished && sink.finished) {
+        return false
+      }
     }
     connection.removeStream(id)
     return true