RFR: 8266904: Use function pointer typedefs in OopOopIterateDispatch

[Ioi Lam]

On Tue, 11 May 2021 19:44:24 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> The way our OopIterateClosures are devirtualized is quite complex. I think we can lower the complexity a tiny bit by using a function pointer typedef.

LGTM

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Marked as reviewed by iklam (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/3986