[test] Fix copy&paste error in bug link.

test/mjsunit/harmony/async-await-basic.js

Index: test/mjsunit/harmony/async-await-basic.js
diff --git a/test/mjsunit/harmony/async-await-basic.js b/test/mjsunit/harmony/async-await-basic.js
index 846baeb3fd416c068c975d2864fca5af31e78705..51572cdb9f79277ade7843610a7da2122b210822 100644
--- a/test/mjsunit/harmony/async-await-basic.js
+++ b/test/mjsunit/harmony/async-await-basic.js
@@ -370,7 +370,7 @@ assertEqualsAsync(
 assertThrows(() => eval("async({ foo = 1 })"), SyntaxError);
 assertThrows(() => eval("async(a, { foo = 1 })"), SyntaxError);
 
-// https://bugs.chromium.org/p/chromium/issues/detail?id=628984
+// https://bugs.chromium.org/p/chromium/issues/detail?id=638019
 async function gaga() {
   let i = 1;
   while (i-- > 0) { await 42 }