RFR: 8289659: Refactor I/O stream copying to use InputStream.readAllBytes in X509CertPath

[Andrey Turbanov]

Use `InputStream.readAllBytes` instead of manually written method.

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Commit messages:
 - [PATCH] Refactor I/O stream copying to use InputStream.readAllBytes in X509CertPath

Changes: https://git.openjdk.org/jdk/pull/9263/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9263&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8289659
  Stats: 20 lines in 1 file changed: 0 ins; 17 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/9263.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9263/head:pull/9263

PR: https://git.openjdk.org/jdk/pull/9263