sched::test::dont_starve_1 deadlocks with valgrind and on bsd

[thestinger]

I think this test only works when you have more than one physical/logical core.

[alexcrichton]

Relevant commit is c767643
Relevant logs are http://buildbot.rust-lang.org/builders/snap3-mac/builds/372/steps/test/logs/stdio
Relevant test is rt::sched::test::dont_starve_1
Relevant person is @brson

Yay for relativity! or something like that.

[thestinger]

http://buildbot.rust-lang.org/builders/snap3-bsd/builds/137/steps/test/logs/stdio

[alexcrichton]

It was attempted to only run this test when not running on valgrind, but @thestinger noticed that it still failed on bsd, so it was completely removed as a test (the code's still there) in #9412

[brson]

This is because the buildbot configuration sets RUST_RT_TEST_THREADS=1 when valgrinding and this test depends on that value being >1.

[thestinger]

@brson: any idea why it also deadlocks on the BSD bot? I added a workaround for valgrind but it wasn't enough