exit status: 134 with stderr:
swift: /home/buildnode/jenkins/workspace/oss-swift-5.1-package-linux-ubuntu-16_04/llvm/lib/Support/raw_ostream.cpp:735: uint64_t llvm::raw_fd_ostream::seek(uint64_t): Assertion `SupportsSeeking && "Stream does not support seeking!"' failed. Stack dump: 0. Program arguments: swift -frontend -c -enable-experimental-static-assert - swift[0x4938c34] swift[0x4936850] swift[0x4939058] /lib/x86_64-linux-gnu/libpthread.so.0(+0x11390)[0x7f7c86339390] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x38)[0x7f7c84a78428] /lib/x86_64-linux-gnu/libc.so.6(abort+0x16a)[0x7f7c84a7a02a] /lib/x86_64-linux-gnu/libc.so.6(+0x2dbd7)[0x7f7c84a70bd7] /lib/x86_64-linux-gnu/libc.so.6(+0x2dc82)[0x7f7c84a70c82] swift[0x49196b0] swift[0x4919701] swift[0x4657dda] swift[0x4651a63] swift[0x45ed347] swift[0x1eaf048] swift[0x47b2e45] swift[0x47b3423] swift[0x5847c1] swift[0x50a4e4] swift[0x5058cf] swift[0x4a022d] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f7c84a63830] swift[0x49fda9]