[jdk8u-dev] RFR: 8222299: [TESTBUG] move hotspot container tests to hotspot/containers

[yaqsun]

This is a backport of JDK-8222299: [TESTBUG] move hotspot container tests to hotspot/container.

This patch has already been applied to OracleJDK8.

This backport has resolved the conflict about hotspot/test/TEST.groups. doc/testing.html and doc/testing.md do not exist in 8u.

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Commit messages:
 - Backport 66c817134fa012d53128eecfc1bac0c32c678145

Changes: https://git.openjdk.org/jdk8u-dev/pull/488/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=488&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8222299
  Stats: 16 lines in 16 files changed: 14 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/488.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/488/head:pull/488

PR: https://git.openjdk.org/jdk8u-dev/pull/488