Replace breakpoint_reinsert_addr by get_next_pcs operation in GDBServer
This patch in preparation for software single step support on ARM. It refactors
breakpoint_reinsert_addr into get_next_pcs so that multiple location can be
returned.
When software single stepping there can be multiple possible next addresses
because we're stepping over a conditional branch instruction, for example.
The operation get_next_pcs handles that by returning a vector of all the
possible next addresses.
Software breakpoints are installed at each location returned.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }