[fuzzer] Use RawPrint instead of Printf for instrumentation warning

Summary:
Use RawPrint instead of Printf for instrumentation warning because
Printf doesn't work on Win when instrumentation is being
initialized (since OutputFile is not yet initialized).

Reviewers: kcc

Reviewed By: kcc

Differential Revision: https://reviews.llvm.org/D57531

llvm-svn: 352789
GitOrigin-RevId: fc7faecb401c1ef50c8f71594aad16cb150eb987
2 files changed