Implement min max minOf maxOf functions for unsigned types (KT-30035)

libraries/stdlib/test/unsigned/UMathTest.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package test.unsigned
+
+import kotlin.math.max
+import kotlin.math.min
+import kotlin.test.Test
+import kotlin.test.expect
+
+class UMathTest {
+
+    @Test
+    fun min() {
+        expect(1uL) { min(2uL, 1uL) }
+        expect(ULong.MIN_VALUE) { min(ULong.MIN_VALUE, ULong.MAX_VALUE) }
+        expect(58u) { min(58u, 1u shl 31) }
+        expect(42312u) { min(42312u, 42312u) }
+    }
+
+    @Test
+    fun max() {
+        expect(2u) { max(2u, 1u) }
+        expect(UInt.MAX_VALUE) { maxOf(UInt.MIN_VALUE, UInt.MAX_VALUE) }
+        expect(1uL shl 63) { max(58uL, 1uL shl 63) }
+        expect(42312uL) { maxOf(42312uL, 42312uL) }
+    }
+}