Fix printing of types in initializers with suppressed tags.

Tag and specifier printing can be suppressed in Decl::printGroup, but these suppressions leak into the initializers. Thus

int *x = ((void *)0), *y = ((void *)0);

gets printed as

int *x = ((void *)0), *y = ((*)0);

And

struct { struct Z z; } z = {(struct Z){}};

gets printed as

struct { struct Z z; } z = {(){}};

The stops the suppressions from leaking into the initializers.

Patch by Nick Sumner!

Differential Revision: http://reviews.llvm.org/D16438

llvm-svn: 258679