[asan] Remove use_odr_indicator runtime flag

Summary:
Flag was added for testing 3 years ago. Probably it's time
to simplify code and usage by removing it.

Reviewers: eugenis, m.ostapenko

Subscribers: mehdi_amini, kubamracek, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D55254

llvm-svn: 348315