RFR: 8318130: SocksSocketImpl needlessly encodes hostname for IPv6 addresses

[Daniel Jeliński]

This patch fixes the encoding of IPv6 addresses in the URI provided to ProxySelector.

The original code percent-encoded the square brackets added around the IPv6 addresses, producing URIs that could not be parsed correctly.

The proposed code does not percent-encode the IPv6 addresses at all.

Added a test to verify that different forms of addresses are processed correctly. The test verifies the handling of IPv4 addresses, IPv6 without scope, IPv6 with numeric scope, IPv6 with textual scope (only if present on the machine running tests), hostnames and FQDNs

Tier1-3 tests passed.

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Commit messages:
 - Do not urlencode IPv6 addresses

Changes: https://git.openjdk.org/jdk/pull/16265/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16265&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318130
  Stats: 215 lines in 2 files changed: 208 ins; 3 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/16265.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16265/head:pull/16265

PR: https://git.openjdk.org/jdk/pull/16265