[sanitizer] Second test fix to tolerate chmod not working as intended

Second attempt to fix a bot failure from
634da7a1 on an Android bot:
https://lab.llvm.org/buildbot#builders/77/builds/14339

With the fix in 986afe84 there was a
different issue, because we need the fully qualified path name to the
binary, which is only available in arg[0]. New failure:
https://lab.llvm.org/buildbot/#/builders/77/builds/14346/steps/16/logs/stdio

Restructure the test so both attempts are made from the same invocation,
which sets up the bad paths directly.