RFR: 8290512: G1: Fix typo in allocation statistics log message

[Thomas Schatzl]

Hi all,

  please review this trivial change to add a whitespace to a log message.

Testing: local compilation

Thanks,
  Thomas

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Commit messages:
 - Typo fixed

Changes: https://git.openjdk.org/jdk/pull/9552/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9552&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290512
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9552.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9552/head:pull/9552

PR: https://git.openjdk.org/jdk/pull/9552