[lldb] Disable deserialization safety for lldb

Deserialization safety prevents reading internal implementation details
from swiftmodules files. Let's disable it for LLDB as these details are
useful for debugging and LLDB enables more deserialization recovery. The
recovery should help handle the same issues avoided by the safety. We
can also expand the recovery more liberally if it crashes under paths
avoided under safety.

Author: xymus

lldb/source/Plugins/TypeSystem/Swift/SwiftASTContext.cpp

@@ -944,6 +944,10 @@ SwiftASTContext::SwiftASTContext(std::string description,
   // for the protocol conforming types.
   lang_opts.AllowModuleWithCompilerErrors = true;
   lang_opts.EnableTargetOSChecking = false;
+
+  // Bypass deserialization safety to allow deserializing internal details from
+  // swiftmodule files.
+  lang_opts.EnableDeserializationSafety = false;
 }
 
 SwiftASTContext::~SwiftASTContext() {