[GWP-ASan] Fix sanitizer backtrace util using wrong print.

The sanitizer backtrace is used in tests, and calling StackTrace.Print()
means that it uses the sanitizer's Printf(), rather than GWP-ASan's
Printf(). In the current code, GWP-ASan's Printf() *is* the sanitizer
print, but this isn't guaranteed to be the case, and will change in an
upcoming patch.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D139748

GitOrigin-RevId: f529a9f324a8eb4a0f2c5e662b6c57a6a775d62f
1 file changed