[libFuzzer] Remove unused version of FuzzedDataProvider.h.

Summary: The actual version lives in compiler-rt/include/fuzzer/.

Reviewers: Dor1s

Reviewed By: Dor1s

Subscribers: delcypher, #sanitizers, llvm-commits

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D67623

llvm-svn: 371997