Reverting problematic commits:

fa500f453d	Alex Tkachman	Today 19:47
725bebc23f	Alex Tkachman	Today 19:36

stdlib/ktSrc/System.kt

@@ -0,0 +1,19 @@
+package std.util
+
+/**
+Executes current block and returns elapsed time in milliseconds
+*/
+fun measureTimeMillis(block: () -> Unit) : Long {
+    val start = System.currentTimeMillis()
+    block()
+    return System.currentTimeMillis() - start
+}
+
+/**
+Executes current block and returns elapsed time in milliseconds
+*/
+fun measureTimeNano(block: () -> Unit) : Long {
+    val start = System.nanoTime()
+    block()
+    return System.nanoTime() - start
+}