-thread-info in lldbmi does not conform to protocol. Should end with current thread id

-thread-info in lldbmi does not conform to protocol. Should end with
current thread id as described here:
https://sourceware.org/gdb/onlinedocs/gdb/GDB_002fMI-Thread-Commands.html#GDB_002fMI-Thread-Commands

When printing all threads, the current thread id should be printed
afterwards.

Example:
-thread-info
     ^done,threads=[
     {id="2",target-id="Thread 0xb7e14b90 (LWP 21257)",
        frame={level="0",addr="0xffffe410",func="__kernel_vsyscall",
                args=[]},state="running"},
     {id="1",target-id="Thread 0xb7e156b0 (LWP 21254)",
        frame={level="0",addr="0x0804891f",func="foo",
                args=[{name="i",value="10"}],
                file="/tmp/a.c",fullname="/tmp/a.c",line="158"},
                state="running"}],
     current-thread-id="1"
     (gdb)

Patch from jacdavis@microsoft.com

Reviewers: zturner, chuckr

Differential Revision: http://reviews.llvm.org/differential/revision/edit/18880/

llvm-svn: 265858