Add powerpc support for the test suite.

Reviewed by Ed Maste at MeetBSD.
Add an alternative CFA type.

Summary:
PowerPC handles the stack chain with the current stack pointer being a pointer
to the backchain (CFA).  LLDB currently has no way of handling this, so this
adds a "CFA is dereferenced from a register" type.

Discussed with Jason Molenda, who also provided the initial patch for this.

Reviewers: jasonmolenda

Reviewed By: jasonmolenda

Subscribers: emaste, lldb-commits

Differential Revision: http://reviews.llvm.org/D6182
Improve PowerPC unwind support

Summary:
Taking advantage of the new 'CFAIsRegisterDereferenced' CFA register type, add
full stack unwind support to the PowerPC/PowerPC64 ABI.  Also, add a new
register set for powerpc32-on-64, so the register sizes are correct.  This also
requires modifying the ProcessMonitor to add support for non-uintptr_t-sized
register values.

Reviewers: jasonmolenda, emaste

Subscribers: emaste, lldb-commits

Differential Revision: http://reviews.llvm.org/D6183
FIx a bug with PC-register handling in a RA register.

The addition of RegisterNumber introduced a bug where if the PC is stored in a
return address register, such as on ARM and PowerPC, this register number is
retrieved and used, but never checked in the row if it's saved.  Correct this by
setting the variable that's used to the new register number.

Patch by Jason Molenda.
Add support for small-model PIC for PowerPC.

Summary:
Large-model was added first.  With the addition of support for multiple PIC
models in LLVM, now add small-model PIC for 32-bit PowerPC, SysV4 ABI.  This
generates more optimal code, for shared libraries with less than about 16380
data objects.

Test Plan: Test cases added or updated

Reviewers: joerg, hfinkel

Reviewed By: hfinkel

Subscribers: jholewinski, mcrosier, emaste, llvm-commits

Differential Revision: http://reviews.llvm.org/D5399