Remove convoluted getCompatibleInputs logic

Given this method has a return type of Collection, there is no need to
use an ordered set or to then build that set into a list.

Author: hinerm

src/main/java/org/scijava/convert/AbstractConvertService.java

@@ -106,15 +106,15 @@ public boolean supports(final Class<?> src, final Type dest) {
 
 	@Override
 	public Collection<Object> getCompatibleInputs(Class<?> dest) {
-		Set<Object> objects = new LinkedHashSet<Object>();
+		Set<Object> objects = new HashSet<Object>();
 
 		for (final Converter<?, ?> c : getInstances()) {
 			if (dest.isAssignableFrom(c.getOutputType())) {
 				c.populateInputCandidates(objects);
 			}
 		}
 
-		return new ArrayList<Object>(objects);
+		return objects;
 	}
 
 	@Override