Reduce the number of builtin operator overload candidates added in certain

Reduce the number of builtin operator overload candidates added in certain
cases. First, omit all builtin overloads when no non-record type is in the set
of candidate types. Second, avoid arithmetic type overloads for non-arithmetic
or enumeral types (counting vector types as arithmetic due to Clang
extensions). When heavily using constructs such as STL's '<<' based stream
logging, this can have a significant impact. One logging-heavy test case's
compile time dropped by 10% with this. Self-host shows 1-2% improvement in
compile time, but that's likely in the noise.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@121665 91177308-0d34-0410-b5e6-96231b3b80d8