COMMA_IN_WHEN_CONDITION_WITHOUT_ARGUMENT is an ERROR now.

Migrated code.
Updated test data in IDE tests.
Dropped whenWithRangeTestsAndMultiConditions.kt:
"Introduce subject" is not applicable to 'when' with ||-ed conditions.

idea/testData/intentions/branched/ifWhen/whenToIf/whenWithMultiConditions.kt

@@ -1,6 +1,6 @@
 fun test(n: Int): String {
     return <caret>when {
-        n < 0, n > 1000 -> "unknown"
+        n < 0 || n > 1000 -> "unknown"
         n <= 10 -> "small"
         n <= 100 -> "average"
         else -> "big"

idea/testData/intentions/branched/when/introduceSubject/whenWithNondivisibleConditions.kt

@@ -3,7 +3,7 @@ fun test(n: Int): String {
     return <caret>when {
         n in 0..10 -> "small"
         n >= 10 && n <= 100 -> "average"
-        n < 0, n > 1000 -> "unknown"
+        n < 0 || n > 1000 -> "unknown"
         else -> "big"
     }
 }

idea/testData/intentions/branched/when/introduceSubject/whenWithRangeTestsAndMultiConditions.kt

@@ -1,8 +0,0 @@
-fun test(n: Int): String {
-    return <caret>when {
-        n in 0..5, n in 5..10 -> "small"
-        n in 10..50, n in 50..100 -> "average"
-        n in 100..500, n in 500..1000 -> "big"
-        else -> "unknown"
-    }
-}

idea/testData/intentions/branched/when/introduceSubject/whenWithRangeTestsAndMultiConditions.kt.after

@@ -1,8 +0,0 @@
-fun test(n: Int): String {
-    return <caret>when (n) {
-        in 0..5, in 5..10 -> "small"
-        in 10..50, in 50..100 -> "average"
-        in 100..500, in 500..1000 -> "big"
-        else -> "unknown"
-    }
-}