[master] RFR: Enforce +UseCompressedClassPointers [v2]

[Roman Kennke]

> This change force-enables +UseCompressedClassPointers. This is required for the next step where we want to store the compressed class pointers into object headers. The change also removes test configurations that explicitely disable CCP.
> In the long run, we would remove the flag altogether, but not now.
> 
> Testing:
>  - [x] tier1
>  - [x] tier2

Roman Kennke has updated the pull request incrementally with two additional commits since the last revision:

 - Update test/hotspot/jtreg/gc/metaspace/TestSizeTransitions.java
   
   Co-authored-by: Aleksey Shipilëv <aleksey.shipilev at gmail.com>
 - Update src/hotspot/share/runtime/arguments.cpp
   
   Co-authored-by: Aleksey Shipilëv <aleksey.shipilev at gmail.com>

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

Changes:
  - all: https://git.openjdk.java.net/lilliput/pull/5/files
  - new: https://git.openjdk.java.net/lilliput/pull/5/files/a6273965..648080bf

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=lilliput&pr=5&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=lilliput&pr=5&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/lilliput/pull/5.diff
  Fetch: git fetch https://git.openjdk.java.net/lilliput pull/5/head:pull/5

PR: https://git.openjdk.java.net/lilliput/pull/5