RFR: 8297749: Remove duplicate space in the ProtocolException message being thrown from HttpURLConnection

[Johnny Lim]

This PR removes a duplicate space in `ProtocolException` message.

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Commit messages:
 - Remove duplicate space in ProtocolException message

Changes: https://git.openjdk.org/jdk/pull/11002/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11002&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8297749
  Stats: 3 lines in 2 files changed: 0 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/11002.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11002/head:pull/11002

PR: https://git.openjdk.org/jdk/pull/11002