[analyzer] Fix unknown block calls to have zero parameters.

Right now they report to have one parameter with null decl,
because initializing an ArrayRef of pointers with a nullptr
yields an ArrayRef to an array of one null pointer.

Fixes a crash in the OSObject section of RetainCountChecker.

Differential Revision: https://reviews.llvm.org/D55671


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@349229 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed