[clang-tidy] Ignore implicit functions in performance-unnecessary-value-param

Summary:
The performance-unnecessary-value-param check mangled inherited
constructors, as the constructors' parameters do not have useful source
locations. Fix this by ignoring implicit functions.

Fixes PR31684.

Reviewers: flx, alexfh, aaron.ballman

Subscribers: madsravn, JDevlieghere, cfe-commits

Differential Revision: https://reviews.llvm.org/D29018

llvm-svn: 292786