Prepare to rename RTC_NOTREACHED to RTC_DCHECK_NOTREACHED

Add implementation of RTC_DCHECK_NOTREACHED equal to the RTC_NOTREACHED.
The new macros will replace the old one when old one's usage will be
removed. The idea of the renaming to provide a clear signal that this
is debug build only macros and will be stripped in the production build.

Bug: webrtc:9065
Change-Id: I4c35d8b03e74a4b3fd1ae75dba2f9c05643101db
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/237802
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35348}
diff --git a/rtc_base/async_tcp_socket.cc b/rtc_base/async_tcp_socket.cc
index bc8b7dd..c248075 100644
--- a/rtc_base/async_tcp_socket.cc
+++ b/rtc_base/async_tcp_socket.cc
@@ -99,7 +99,7 @@
     case Socket::CS_CONNECTED:
       return STATE_CONNECTED;
     default:
-      RTC_NOTREACHED();
+      RTC_DCHECK_NOTREACHED();
       return STATE_CLOSED;
   }
 }
@@ -143,7 +143,7 @@
       break;
     }
     if (static_cast<size_t>(res) > view.size()) {
-      RTC_NOTREACHED();
+      RTC_DCHECK_NOTREACHED();
       res = -1;
       break;
     }
@@ -217,7 +217,7 @@
 
   if (size > inbuf_.size()) {
     RTC_LOG(LS_ERROR) << "input buffer overflow";
-    RTC_NOTREACHED();
+    RTC_DCHECK_NOTREACHED();
     inbuf_.Clear();
   } else {
     inbuf_.SetSize(size);
@@ -323,7 +323,7 @@
     case Socket::CS_CONNECTING:
       return State::kBound;
     default:
-      RTC_NOTREACHED();
+      RTC_DCHECK_NOTREACHED();
       return State::kClosed;
   }
 }