Performance improvement: Change lldb so that it puts a breakpoint

on the first branch instruction after a function return (or the end
of a source line), instead of a breakpoint on the return address,
to skip an extra stop & start of the inferior process.

I changed Process::AdvanceAddressToNextBranchInstruction to not
take an optional InstructionList argument - no callers are providing
a cached InstructionList today, and if this function was going to
do that, the right thing to do would be to fill out / use a
DisassemblerSP which is a disassembler with the InstructionList for
this address range.


http://reviews.llvm.org/D15708
<rdar://problem/23309838> 

llvm-svn: 257117