Summary: When run under llvm-mc-disassemble-fuzzer, there is no symbol lookup callback so tryAddingSymbolicOperand() must fail gracefully instead of crashing Reviewers: aemerson, javed.absar Reviewed By: aemerson Subscribers: lhames, kristof.beyls, llvm-commits Differential Revision: https://reviews.llvm.org/D51005 llvm-svn: 340287