RFR: 8258534: Epsilon: clean up unused includes

[Jie Fu]

On Fri, 11 Dec 2020 05:03:56 GMT, Lehua Ding <github.com+13173904+lhtin at openjdk.org> wrote:

> Hi all,
> 
> CLion IDE shows two warnings of unused includes(`#include "utilities/macros.hpp"`) in EpsilonGC's code. these maybe can be removed.
> 
> Testing: macosx-x86_64-server-{release,fastdebug,slowdebug}

Marked as reviewed by jiefu (Committer).

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PR: https://git.openjdk.java.net/jdk/pull/1745