OpenEXR-9999 Ebuild fails at src_prepare #fix path for testsuite without test USE flag enabled

[SyntaxSnack]

It seems to be looking for a files named tmpDir.h in the OpenEXRFuzzTest and OpenEXRUtilTest directories that do exist, but I cannot find tmpDir.h anywhere in the head of the main branch.

This happens even without the test use flag, so I'm not sure this directory is even used for the build without -DBUILD_TESTING triggered in cmake by the test use flag.