RFR: javac should not place initializers of null restricted fields before the super invocation

[Vicente Romero]

javac is automatically placing the initializers of null restricted fields before the super invocation. This is incorrect, null restricted fields are not strict and those initializers should be placed after the super. But javac will check that null restricted fields have been initialized before a super invocation. This implies that null restricted fields should not have initializers and users should manually initialize them in all the constructors and before explicit super invocations.

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

Commit messages:
 - initializers of non null fields are placed after super

Changes: https://git.openjdk.org/valhalla/pull/1990/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1990&range=00
  Stats: 191 lines in 11 files changed: 82 ins; 71 del; 38 mod
  Patch: https://git.openjdk.org/valhalla/pull/1990.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1990/head:pull/1990

PR: https://git.openjdk.org/valhalla/pull/1990