Include javax.* sources in the bazel rule for java emul, so j2cl shares those as well

Change-Id: Ice7efda2c243beb56f038a5f4379ad87149c8267

user/BUILD.bazel

diff --git a/user/BUILD.bazel b/user/BUILD.bazel
index 5db8591..07eb500 100644
--- a/user/BUILD.bazel
+++ b/user/BUILD.bazel
@@ -6,7 +6,10 @@
 
 filegroup(
     name = "java_emul",
-    srcs = glob(["super/com/google/gwt/emul/java/**/*.java"]),
+    srcs = glob([
+        "super/com/google/gwt/emul/java/**/*.java",
+        "super/com/google/gwt/emul/javax/**/*.java",
+        ]),
 )
 
 filegroup(