Patch: Java: Fix missed GGC root registration

[Bryce McKinlay]

Bryce McKinlay wrote:

> The struct binding_level in java/decl.c lacked ggc type/root 
> registration markers. This resulted in occasional tree corruption bugs 
> when compiling bytecode using the gcj-abi branch because the 
> current_binding_level->stmts could be freed by the GC when compiling 
> some class files.
>
> This patch adds the appropriate markers and roots registration.
>
> OK for mainline and 3.4 branch?


Actually, it turns out this is a tree-ssa specific bug - it applies only 
to mainline.

Bryce