protected String buildTestFileDesignator(int fileIndex, String filePath) {
		return null;
	}
Get CUint file designator if use of A, B, C... is not suitable.
@param fileIndex file index within sorted list
@param filePath binary file path
@return short file designator for use in qualified test name
Ghidra/Features/Base/src/main/java/ghidra/test/processors/support/ProcessorEmulatorTestAdapter.java