Warn about comma-separated conditions in when without argument.

See KT-5143.

idea/testData/quickfix/migration/commasInWhenWithoutArgument/commasInConditionWithNoArguments.kt

@@ -0,0 +1,9 @@
+// "Replace ',' with '||' in when" "true"
+fun test(i: Int, j: Int) {
+    var b = false
+    when {
+        i > 0<caret>, j > 0 -> { /* some code 1 */ }
+        i < 0, j < 0 -> { /* some code 2 */ }
+        else -> { /* other code */ }
+    }
+}