Delete root header file typedef.h.

Usage replaced with stdint.h, rtc_base/system/arch.h and
rtc_base/system/unused.h, as appropriate.

Bug: webrtc:6854
Change-Id: I97225465d14b969903d92979e2df3c3c05d35f18
Reviewed-on: https://webrtc-review.googlesource.com/90249
Reviewed-by: Niklas Enbom <niklas.enbom@webrtc.org>
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24100}

logging/BUILD.gn

@@ -66,7 +66,6 @@ rtc_source_set("rtc_event_pacing") {
 
   deps = [
     ":rtc_event_log_api",
-    "../:typedefs",
     "../rtc_base:ptr_util",
     "//third_party/abseil-cpp/absl/memory",
   ]