RFR: 8280010: Remove double buffering of InputStream for Properties.load

[Andrey Turbanov]

`Properties.load` uses `java.util.Properties.LineReader`. LineReader already buffers input stream. Hence wrapping InputStream in BufferedInputStream is redundant.

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Commit messages:
 - [PATCH] Remove double buffering of InputStream for Properties.load
 - [PATCH] Remove double buffering of InputStream for Properties.load

Changes: https://git.openjdk.java.net/jdk/pull/7021/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7021&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8280010
  Stats: 30 lines in 8 files changed: 0 ins; 11 del; 19 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7021.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7021/head:pull/7021

PR: https://git.openjdk.java.net/jdk/pull/7021