Put the current pc arrow back into the default disassembly format.
I went back and forth on removing this - and tried dropping it for
a few weeks.  But when you're working at an assembly language, it
really is helpful to have this displayed to show where the current
pc is.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@221682 91177308-0d34-0410-b5e6-96231b3b80d8