[lworld] RFR: 8288135: [lworld] Implement HotSpot flag -XX:+EnablePrimitiveClasses [v2]

[David Simms]

> Runtime component of -XX:+EnablePrimitiveClasses switch

David Simms has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:

 - Merge branch 'lworld' into 8288135
   
   # Conflicts:
   #	test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestC2CCalls.java
   #	test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestDeoptimizationWhenBuffering.java
   #	test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestNewAcmp.java
   #	test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestTrivialMethods.java
   #	test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestUnloadedReturnTypes.java
   #	test/hotspot/jtreg/runtime/valhalla/inlinetypes/InlineOops.java
   #	test/hotspot/jtreg/runtime/valhalla/inlinetypes/InlineTypeDensity.java
   #	test/hotspot/jtreg/runtime/valhalla/inlinetypes/ValueTearing.java
 - Be explicit about which features are enabled in testing
 - Missed preload processing
 - Merge branch 'lworld' into 8288135
 - Merge branch 'lworld' into 8288135
 - Merge branch 'lworld' into 8288135
 - Retain the classfile version checks AND enable flag
 - Silently disable the default on setting if Valhalla is disabled
 - 8288135: [lworld] Implement HotSpot flag -XX:+EnablePrimitiveClasses

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

Changes: https://git.openjdk.org/valhalla/pull/727/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=727&range=01
  Stats: 1136 lines in 120 files changed: 805 ins; 56 del; 275 mod
  Patch: https://git.openjdk.org/valhalla/pull/727.diff
  Fetch: git fetch https://git.openjdk.org/valhalla pull/727/head:pull/727

PR: https://git.openjdk.org/valhalla/pull/727