Recently added entry point renaming file referred to
test source file hlsl.entry.rename.frag via relative directory.
Change it to be consistent with other tests: assume test
sources are in the current directory.
Use "--source-entrypoint name" on the command line, or the
TShader::setSourceEntryPoint(char*) API.
When the name given to the above interfaces is detected in the
shader source, it will be renamed to the entry point name supplied
to the -e option or the TShader::setEntryPoint() method.