Improve pthread_create failure handling.

Return EAGAIN rather than aborting if we fail to set up the TLS for a new
thread.

Add a test that uses all the VMAs so we can properly test these edge cases.

Add an explicit test for pthread_attr_setdetachstate, which we use in the
previous test, but other than that has no tests.

Remove support for ro.logd.timestamp/persist.logd.timestamp, which doesn't
seem to be used, and which prevents us from logging failures in cases where
mmap fails (because we need to mmap in the system property implementation).

Bug: http://b/65608572
Test: ran tests
Change-Id: I9009f06546e1c2cc55eff996d08b55eff3482343