Add the capability to display the number of supported hardware watchpoints to the "watchpoint list" command.

Add default Process::GetWatchpointSupportInfo() impl which returns an error of "not supported".
Add "qWatchpointSupportInfo" packet to the gdb communication layer to support this, and modify TestWatchpointCommands.py to test it.

llvm-svn: 157345
diff --git a/lldb/tools/debugserver/source/MacOSX/MachProcess.cpp b/lldb/tools/debugserver/source/MacOSX/MachProcess.cpp
index 83cbe2c..dd09745 100644
--- a/lldb/tools/debugserver/source/MacOSX/MachProcess.cpp
+++ b/lldb/tools/debugserver/source/MacOSX/MachProcess.cpp
@@ -944,6 +944,12 @@
     }
 }
 
+uint32_t
+MachProcess::GetNumSupportedHardwareWatchpoints () const
+{
+    return m_thread_list.NumSupportedHardwareWatchpoints();
+}
+
 bool
 MachProcess::EnableBreakpoint(nub_break_t breakID)
 {