[jdk8u-dev] RFR: 8295322: Tests for JDK-8271459 were not backported to 11u

[Alexey Pavlyutkin]

Hi!

Here is the backport of [JDK-8295322](https://bugs.openjdk.org/browse/JDK-8295322) that adds missed tests for [JDK-8271459](https://bugs.openjdk.org/browse/JDK-8271459). Except the path shuffling the following changes were done to the original https://github.com/openjdk/jdk11u-dev/commit/70ddb1b025ce3b8eed4d8ad5af1b1fa4d0e0b015

- visibility of test class and methods was changed to `public` to support older JTReg
- `requires` annotation was removed to support older JTReg

Verification (amd64/20.04 LTS): running new `hotspot/test/compiler/c2/TestNegativeStringBuilderCapacity.java`

7 of 7 PASS on https://github.com/openjdk/jdk8u-dev/commit/dfeeceb224a62bd7ffbe5adfd36eebe6c853935a (integration of [JDK-8271459](https://bugs.openjdk.org/browse/JDK-8271459))
4 of 7 FAIL on the previous https://github.com/openjdk/jdk8u-dev/commit/43cfe27fa3a11dd6d4fffcb1c1336ac7fdd0233b

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Commit messages:
 - removing unwanted delta
 - support an older JTReg

Changes: https://git.openjdk.org/jdk8u-dev/pull/152/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=152&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295322
  Stats: 186 lines in 1 file changed: 186 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/152.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev pull/152/head:pull/152

PR: https://git.openjdk.org/jdk8u-dev/pull/152