RFR: 6671: Eagerly convert end time to the same unit as start time

[Henrik Dafgård]

Set event end time to use the same unit as start time when accessing the values, rather than when comparing between them.

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Commits:
 - f27518aa: Eagerly convert end time to the same unit as start time

Changes: https://git.openjdk.java.net/jmc/pull/30/files
 Webrev: https://webrevs.openjdk.java.net/jmc/30/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JMC-6671
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jmc/pull/30.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/30/head:pull/30

PR: https://git.openjdk.java.net/jmc/pull/30