In preparation for identifying an addr2line sentinel. See previous work
[0], which applies a similar change to perf.

[0] commit 8dc26b6f ("perf srcline: Make sentinel reading for binutils
addr2line more robust")
Signed-off-by: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
Link: https://lore.kernel.org/r/20240415145538.1938745-5-bjohannesmeyer@gmail.comSigned-off-by: Josh Poimboeuf <jpoimboe@kernel.org>