Fix two clang-tidy issues in crasher.cpp.

TEMP_FAILURE_RETRY's result was unused for the call to read(), so now
mark it as such to silence a possible unused result warning. For
__read_chk(), this function is an internal implementation detail of
FORTIFY in Bionic. Under clang-tidy, FORTIFY checks are actually
removed, so this now results in an unknown function being called. The
code should not be explicitly depending on an implementation detail, but
we can just suppress the failing case to retain test coverage of the
actual implementation.

Bug: http://b/110779387
Test: Build using WITH_TIDY=1
Change-Id: If83ac1d6f3b6dc32c0d0fb56d8e675e53b586f78