RFR (S) 8180482: Reformat -XX:+PrintSafepointStatistics table

[Aleksey Shipilev]

https://bugs.openjdk.java.net/browse/JDK-8180482

Current table is garbled because VM ops names are too long, headers are not
accounted in format specifiers, etc.

Patch:
  http://cr.openjdk.java.net/~shade/8180482/webrev.01/

Before/after:
  http://cr.openjdk.java.net/~shade/8180482/before.txt
  http://cr.openjdk.java.net/~shade/8180482/after.txt

Thanks,
-Aleksey