RFR: 8286386: Address possibly lossy conversions in java.net.http

[Daniel Fuchs]

In relation to [JDK-8244681](https://bugs.openjdk.java.net/browse/JDK-8244681), please find here a patch that addresses possibly lossy conversions in java.net.http

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Commit messages:
 - Fix comments
 - 8286386: Address possibly lossy conversions in java.net.http

Changes: https://git.openjdk.java.net/jdk/pull/8656/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8656&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8286386
  Stats: 27 lines in 3 files changed: 15 ins; 0 del; 12 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8656.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8656/head:pull/8656

PR: https://git.openjdk.java.net/jdk/pull/8656