RFR (XS) 8043164: Format warning in traceStream.hpp

[David Chase]

bug: https://bugs.openjdk.java.net/browse/JDK-8043164
webrev: http://cr.openjdk.java.net/~drchase/8043164/webrev.00/
fix: add appropriate cast to int64_t for INT64_FORMAT

testing:
Compiled with bug-tickling configuration on
  MacOS Mountain Lion (10.8) XCode 4.6.3
  Mavericks (10.9) XCode (4.6.3 and 5.1).
Verified that there were not other warnings tickled by this particular build configuration on either platform.
Also retested with fastdebug build on Mavericks.