[ASan] fix flakiness of Linux-specific clone_test: waitpid should better be provided with __WCLONE option, otherwise it didn't wait for the subprocess, returned -1, and we went crushing the subprocess stack
[ASan] fix flakiness of Linux-specific clone_test: waitpid should better be provided with __WCLONE option, otherwise it didn't wait for the subprocess, returned -1, and we went crushing the subprocess stack

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@162842 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt