Swift master broken on centos

I was testing swift on centos and saw a breakage on apple/swift:master in the SwiftRuntimeLongTests:

SwiftRuntimeLongTests: /home/asb/Developer/swift/swift/unittests/runtime/LongTests/LongRefcounting.cpp:52: void deinitTestObject(swift::HeapObject *): Assertion `object->Addr && "object already deallocated"' failed.

Program received signal SIGABRT, Aborted.
0x00007ffff5ff91f7 in raise () from /lib64/libc.so.6

I'm going to bisect to figure out which commit introduced the crash, and then figure out why it appears on centos and not Ubuntu