Move libFuzzer to compiler_rt.

Resulting library binaries will be named libclang_rt.fuzzer*, and will
be placed in Clang toolchain, allowing redistribution.

Differential Revision: https://reviews.llvm.org/D36908

llvm-svn: 311407
GitOrigin-RevId: 10ab2ace1359fd96cd662ad235797e29f9ba3daa
201 files changed