Removed some questionable default arguments from setters

Summary:
They can be confusing -- what does it mean to call a setter without a
value? Also, some setters, like `setPrintTemplateTree` had `false` as
the default value!

The callers are largely not using these default arguments anyway.

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67491

llvm-svn: 371731