Combine provisioning code for tests and improve logging

Merge from Widevine repo of http://go/wvgerrit/169018

This CL adds a provisioning holder that attempts to
provision and logs the request and response for
failures. The server team can replay the request to debug
problems on their end.

Bug: 276464340
Test: ran cast and ota tests
Change-Id: I6eed117e504ae3287f2ba16c3c507cfdc7456f8d

libwvdrmengine/cdm/core/test/url_request.cpp

@@ -217,8 +217,8 @@ bool UrlRequest::PostRequestWithPath(const std::string& path,
 
   const int ret = socket_.WriteAndLogErrors(
       request.c_str(), static_cast<int>(request.size()), kWriteTimeoutMs);
-  LOGV("HTTP request: (%zu): %s", request.size(),
-       wvutil::b2a_hex(request).c_str());
+  LOGV("HTTP request: (%zu): %s", request.size(), request.c_str());
+  LOGV("HTTP request hex: %s", wvutil::b2a_hex(request).c_str());
   return ret != -1;
 }