fix build bots after f5ac23b5

The old member was `= 0`:
https://github.com/llvm/llvm-project/commit/f5ac23b5ae090d64d31f0b6624470af97dc20bf6#diff-7781d63141d53242da0520361a554df579ecb079b33bdcfbe7a0db95d44cca49L1740

It looks like this caused some bots to fail:
https://lab.llvm.org/buildbot/#/builders/127/builds/21684