Fix segfault when doing `thread info` on a thread without stop info.
Fix segfault when doing `thread info` on a thread without stop info.

Summary:
E.g., if thread 1 hits a breakpoint, then a `thread info` on thread 2 will cause
a segfault, since thread 2 will have no stop info (intended behavior?).

Reviewers: kubabrecka, clayborg

Reviewed By: clayborg

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D8905

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@234437 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb