RFR: 8255245: C1: Fix output of -XX:+PrintCFGToFile to open it with visualizer

[Vladimir Kozlov]

On Fri, 23 Oct 2020 13:16:27 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

> [JDK-8251093](https://bugs.openjdk.java.net/browse/JDK-8251093) introduced some improved logging for intervals. When specifying `-XX:+PrintCFGToFile` to dump the graph to a file to later open it with the C1 visualizer, it also uses the improved interval printing. However, this output can no longer be read by the C1 Visualizer. As the C1 Visualizer is not part of the JDK, we should include the old format again for the output produced by `-XX:+PrintCFGToFile` to be compatible with the visualizer again. The console output can still use the improved logging of JDK-8251093.

Good.

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/837