[jdk11u-dev] RFR: 8273314: Add tier4 test groups

[Aleksey Shipilev]

Semi-clean backport to improve testing in 11u. There seemed to a little trailing whitespace in langtools TEST.groups, which broke the cleanliness. I resolved that by hand. Attn @RealCLanger ;)

Additional testing:
 - [x] Linux x86_64 fastdebug `jdk:tier4` passes with a few known testbugs

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Commit messages:
 - Backport 1f8af524ffe2d2d1469d8f07887b1f61c6e4d7b8

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/477/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=477&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273314
  Stats: 21 lines in 4 files changed: 20 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/477.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/477/head:pull/477

PR: https://git.openjdk.java.net/jdk11u-dev/pull/477