Dumps data about processes and threads.

Code mostly from https://cs.chromium.org/chromium/src/third_party/catapult/systrace/atrace_helper/jni/.

Next step:
- integrate into codebase rather than have as a stand-alone tool


Bug:73058765
Change-Id: Idfefa25488fb3e4db4194aa1da5dc23165f98955
diff --git a/BUILD.gn b/BUILD.gn
index 4160417..6b38d69 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -28,6 +28,7 @@
     ":perfetto_unittests",
     "src/ipc/protoc_plugin:ipc_plugin($host_toolchain)",
     "src/protozero/protoc_plugin($host_toolchain)",
+    "tools/dump_process_data",
     "tools/ftrace_proto_gen:ftrace_proto_gen",
     "tools/proto_to_cpp",
     "tools/trace_to_text",