make tests output spin on the same line by default

dm/DMReporter.cpp

 #include "DMReporter.h"
 
 #include "SkCommandLineFlags.h"
+#include "OverwriteLine.h"
 
 DEFINE_bool(quiet, false, "If true, don't print status updates.");
 
 namespace DM {
 
 void Reporter::updateStatusLine() const {
     if (FLAGS_quiet) {
         return;
     }
 
     SkString status;
-    status.printf("\r\033[K%d tasks left", this->started() - this->finished());
+    status.printf("%s%d tasks left", kSkOverwriteLine, this->started() - this->finished());
     const int failed = this->failed();
     if (failed > 0) {
         status.appendf(", %d failed", failed);
     }
     SkDebugf(status.c_str());
 }
 
 int32_t Reporter::failed() const {
     SkAutoMutexAcquire reader(&fMutex);
     return fFailures.count();
 }
 
 void Reporter::fail(SkString name) {
     SkAutoMutexAcquire writer(&fMutex);
     fFailures.push_back(name);
 }
 
 void Reporter::getFailures(SkTArray<SkString>* failures) const {
     SkAutoMutexAcquire reader(&fMutex);
     *failures = fFailures;
 }
 
 }  // namespace DM