RFR: 8288623: Move Continuation classes out of javaClasses.hpp

[Ioi Lam]

javaClasses.hpp is getting too big - it contains the C++ representation of over 50 Java classes.

The RFE moves the following classes into a new file, continuationJavaClasses.hpp. The naming follows the same pattern as the existing header share/jvmci/jvmciJavaClasses.hpp.

- jdk_internal_vm_ContinuationScope
- jdk_internal_vm_Continuation
- jdk_internal_vm_StackChunk

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Commit messages:
 - 8288623: Move Continuation classes out of javaClasses.hpp

Changes: https://git.openjdk.org/jdk/pull/9191/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9191&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8288623
  Stats: 1032 lines in 9 files changed: 580 ins; 441 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/9191.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9191/head:pull/9191

PR: https://git.openjdk.org/jdk/pull/9191