[clang-tidy] Adding Fuchsia checker for overloaded operators

Adds a check to the Fuchsia module to warn if an operator is overloaded,
except move and copy operators.

See https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md for
reference.

Differential Revision: https://reviews.llvm.org/D41363

llvm-svn: 321363