Update j2cl to depend on JDT release 4.6.
Update j2cl to depend on JDT release 4.6.

Some Java 8 constructs (intersection types) are not surfaced properly by 4.5 APIs.

PiperOrigin-RevId: 136609389

google/j2cl,google/j2cl,google/j2cl,google/j2cl,google/j2cl