Fix reference to llvm_profdata

This is a follow up fix to crrev.com/c/6249273, which breaks
linux-fuzz-coverage because llvm_profdata is made a local value
there.

Change llvm_profdata to a globle constant.

Bug: 395162693
Change-Id: I854f104bb30c1d89c2cf2248144a81c754bc6baa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6287087
Reviewed-by: Prakhar Asthana <pasthana@google.com>
Commit-Queue: Prakhar Asthana <pasthana@google.com>
Auto-Submit: Weizhong Xia <weizhong@google.com>
Cr-Commit-Position: refs/heads/main@{#1422713}
NOKEYCHECK=True
GitOrigin-RevId: 9fdb247ba415543f8f5d906a7687d2648b9e0809