add benchmark samepath

Python is 100x faster than Java, 1000x faster than sys
Native is not good accuracy and 2x slower

Author: scivision

example/bench_samepath.m

@@ -0,0 +1,17 @@
+function bench_samepath()
+
+in = mfilename("fullpath") + ".m";
+in2 = 'Readme.md';
+r = fileparts(fileparts(in));
+addpath(r)
+obj = onCleanup(@() rmpath(r));
+
+f = timeit(@() stdlib.samepath(in, in2)) * 1e3;
+n = timeit(@() stdlib.native.samepath(in, in2)) * 1e3;
+s = timeit(@() stdlib.sys.samepath(in, in2)) * 1e3;
+j = timeit(@() stdlib.java.samepath(in, in2)) * 1e3;
+p = timeit(@() stdlib.python.samepath(in, in2)) * 1e3;
+
+fprintf('Full %f\nNative: %f\nSys: %f\nJava: %f\nPython: %f\n', f, n, s, j, p);
+
+end