crash_dump: use /proc/<pid> fd to check tid process membership.

Bug: http://b/34759490
Test: /data/nativetest/debuggerd_test/debuggerd_test32
Test: debuggerd -b `pidof system_server`
Test: debuggerd -b `pidof zygote`
Change-Id: I627692b44977335a9568cd765ad28205f0a61327
1 file changed