8146187: Print develop and nonproduct flags by -XX:+PrintFlags* options in debug build Reviewed-by: gtriantafill, gziemski, dholmes

8147388: Add diagnostic commands to attach JVMTI agent. Reviewed-by: jbachorik, sspitsyn

8149837: String.intern creates morre work than necessary for G1 Summary: Only use the SATB read barrier when reading existing strings from string table, not when adding new strings. Reviewed-by: stefank, kbarrett