RFR: 8284725: Fix include guard in jfrbitset.hpp

[Roman Kennke]

In the fix for #7964 (https://bugs.openjdk.java.net/browse/JDK-8283710) I got the include guard for jfrbitset.hpp wrong. I made it:

SHARE_JFR_LEAKPROFILER_JFRBITMAP_HPP

but it should be:

SHARE_JFR_LEAKPROFILER_JFRBITSET_HPP

Testing:
 - [x] Build
 - [x] tier1

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Commit messages:
 - 8284725: Fix include guard in jfrbitset.hpp

Changes: https://git.openjdk.java.net/jdk/pull/8198/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8198&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284725
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8198.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8198/head:pull/8198

PR: https://git.openjdk.java.net/jdk/pull/8198