[lldb/Plugins] Add Attach capabilities to ScriptedProcess

This patch adds process attach capabilities to the ScriptedProcess
plugin. This doesn't really expects a PID or process name, since the
process state is already script, however, this allows to create a
scripted process without requiring to have an executuble in the target.

In order to do so, this patch also turns the scripted process related
getters and setters from the `ProcessLaunchInfo` and
`ProcessAttachInfo` classes to a `ScriptedMetadata` instance and moves
it in the `ProcessInfo` class, so it can be accessed interchangeably.

This also adds the necessary SWIG wrappers to convert the internal
`Process{Attach,Launch}InfoSP` into a `SB{Attach,Launch}Info` to pass it
as argument the scripted process python implementation and convert it
back to the internal representation.

rdar://104577406

Differential Revision: https://reviews.llvm.org/D143104

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>

lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp

@@ -195,6 +195,34 @@ Status ScriptedProcess::DoResume() {
   return error;
 }
 
+Status ScriptedProcess::DoAttach(const ProcessAttachInfo &attach_info) {
+  Status error = GetInterface().Attach(attach_info);
+  SetPrivateState(eStateRunning);
+  SetPrivateState(eStateStopped);
+  if (error.Fail())
+    return error;
+  // NOTE: We need to set the PID before finishing to attach otherwise we will
+  // hit an assert when calling the attach completion handler.
+  DidLaunch();
+
+  return {};
+}
+
+Status
+ScriptedProcess::DoAttachToProcessWithID(lldb::pid_t pid,
+                                         const ProcessAttachInfo &attach_info) {
+  return DoAttach(attach_info);
+}
+
+Status ScriptedProcess::DoAttachToProcessWithName(
+    const char *process_name, const ProcessAttachInfo &attach_info) {
+  return DoAttach(attach_info);
+}
+
+void ScriptedProcess::DidAttach(ArchSpec &process_arch) {
+  process_arch = GetArchitecture();
+}
+
 Status ScriptedProcess::DoStop() {
   Log *log = GetLog(LLDBLog::Process);