Integrated: 8310664: remove compiler support for primitive classes

[Vicente Romero]

Remove support for primitive classes in the compiler:
 - switches for checking if primitive classes are allowed and code protected by them
 - remove flavors, Q-types, primitive classes related predicates
 - uses of `.ref` `.val` and projections related code
 - parser support for primitive classes
 - removing the PRIMITIVE_CLASS and ACC_PRIMITIVE flags and its uses
 - some minor refactorings and adjustments to regression tests
 - removing Type.ConstantPoolQType

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Commit messages:
 - fixing whitespace issue
 - 8310664: remove compiler support for primitive classes

Changes: https://git.openjdk.org/valhalla/pull/868/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=868&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310664
  Stats: 1219 lines in 156 files changed: 117 ins; 856 del; 246 mod
  Patch: https://git.openjdk.org/valhalla/pull/868.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/868/head:pull/868

PR: https://git.openjdk.org/valhalla/pull/868