[sanitize] Remove stack size limits from secondary threads.
[sanitize] Remove stack size limits from secondary threads.

If pthread_attr_getstack tell us the stack is 2G, why would we doubt that?

Differential Revision: https://reviews.llvm.org/D34169

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@305330 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