RFR: 8276796: gc/TestSystemGC.java large pages subtest fails with ZGC [v2]

[Aleksey Shipilev]

> ZGC would not start when it cannot allocate the heap with `-XX:+UseLargePages`. This makes the `UseLargePages` subtest fail on systems with (default) `nr_hugepages = 0`. It was exposed after [JDK-8269077](https://bugs.openjdk.java.net/browse/JDK-8269077) moved that test config from G1-specific to generic one.
> 
> While fixing this bug, I decided to massage a test a bit: make it consistently choosing the configuration based on GC availability, doing `UseLargePages` tests only for GCs that fall back to non-large pages if not available, added test IDs. This basically goes the other way JDK-8269077 went: put in the GC-specific configs.
> 
> Additional testing:
>  - [x] Linux x86_64 fastdebug, `gc/TestSystemGC.java` (runs all 5 configs)
>  - [x] Linux x86_64 fastdebug, `gc/TestSystemGC.java`, `TEST_VM_OPTS=-XX:+UseSerialGC` (runs 1 config)
>  - [x] Linux x86_64 fastdebug, `gc/TestSystemGC.java`, `TEST_VM_OPTS=-XX:+UseParallelGC` (runs 1 config)
>  - [x] Linux x86_64 fastdebug, `gc/TestSystemGC.java`, `TEST_VM_OPTS=-XX:+UseG1GC` (runs 1 config)
>  - [x] Linux x86_64 fastdebug, `gc/TestSystemGC.java`, `TEST_VM_OPTS=-XX:+UseShenandoahGC` (runs 1 config)
>  - [x] Linux x86_64 fastdebug, `gc/TestSystemGC.java`, `TEST_VM_OPTS=-XX:+UseZGC` (runs 1 config)

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Review comments

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6310/files
  - new: https://git.openjdk.java.net/jdk/pull/6310/files/1edc74c1..15170896

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6310&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6310&range=00-01

  Stats: 6 lines in 1 file changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6310.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6310/head:pull/6310

PR: https://git.openjdk.java.net/jdk/pull/6310