RFR: 8260193: Remove JVM_GetInterfaceVersion() and JVM_DTraceXXX

[Lois Foltan]

On Mon, 1 Feb 2021 18:40:54 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> - JVM_GetInterfaceVersion() was used by "HotSpot Express" (HSX) which allowed the same JDK library to use different version of HotSpot. However, HSX is no longer supported so this API should be removed.
> - Implementations of APIs such as JVM_DTraceActivate, were removed in [JDK-8068976](https://bugs.openjdk.java.net/browse/JDK-8068976), so their declarations should be removed from jvm.h

Marked as reviewed by lfoltan (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/2338