RFR: 8253525: Implement getInstanceSize/sizeOf intrinsics [v3]

[Aleksey Shipilev]

On Mon, 19 Oct 2020 18:13:59 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Aleksey Shipilev has refreshed the contents of this pull request, and previous commits have been removed. The
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>
> Always run graalunit testing with new intrinsics.
> You need to adjust Graal test:
> src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot.test/src/org/graalvm/compiler/hotspot/test/CheckGraalIntrinsics.java

@vnkozlov I added the new block in `CheckGraalIntrinsics.java`, and made sure it passes the entire `compiler/graalunit`
with [JDK-8254785](https://bugs.openjdk.java.net/browse/JDK-8254785) applied.

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PR: https://git.openjdk.java.net/jdk/pull/650