[analyzer] fix bug with 1-bit APSInt types in Z3ConstraintManager

Summary: Clang does not have a corresponding QualType for a 1-bit APSInt, so use the BoolTy and extend the APSInt. Split from D35450. Fixes PR37622.

Reviewers: george.karpenkov, NoQ

Subscribers: mikhail.ramalho, xazax.hun, szepet, rnkovacs, cfe-commits, a.sidorin

Differential Revision: https://reviews.llvm.org/D47603

llvm-svn: 333704