Don't report a compile exception for a missing function before linking (fixes function_exists() and extension_exists() in many cases)

Author: PseudoKnight

src/main/java/com/laytonsmith/core/MethodScriptCompiler.java

@@ -1955,8 +1955,7 @@ private static void optimize(ParseTree tree, Stack<List<Procedure>> procs, Set<C
 				try {
 					f = (Function) FunctionList.getFunction(t.getData());
 				} catch (ConfigCompileException ex) {
-					compilerErrors.add(ex);
-					return;
+					continue;
 				}
 				Set<OptimizationOption> options = NO_OPTIMIZATIONS;
 				if(f instanceof Optimizable) {