RFR: 8310170: Use sp's argument to improve performance of outputStream::indent

[Johan Sjölen]

Hi,

Please consider this small enhancement. `sp` takes a count argument, this was never used by `indent`, let's just use it.

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Commit messages:
 - Use the count argument for sp()

Changes: https://git.openjdk.org/jdk/pull/14502/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14502&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310170
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/14502.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14502/head:pull/14502

PR: https://git.openjdk.org/jdk/pull/14502