HDFFV-8107 testh5diff will fail if build/test in HDF5 source tree
Description:
This is sub-task for "HDFFV-8105 testh5diff.sh uses the wrong operator (-a) in an if statement."
From the HDFFV-8105's update, h5diff test failed if build&test is performed in HDF5 source tree because 'cp' try to copy test files to self dir.
It's addressed by skipping if cp's src dir and dest dir is same.
Also this applied for all other tools under src/tools dir.
No change to the CMakeLists.txt files because CMake cautions/demands that in-source builds be avoided.
Merged from HDF5 trunk r22617.
Tested:
jam (linux32-LE), koala (linux64-LE), ostrich (linuxppc64-BE), tejeda (mac32-LE), linew (solaris-BE), some manual tests as well
