Drop old enum syntax. Comma / semicolon are now a syntactic part of enum entry.

Comma must present now between enum entries, semicolon between last entry & first member, constructor calls must be without colons / specifiers.
A swarm of tests fixed accordingly.

compiler/testData/loadJava/compiledKotlin/enum/enumWithConstuctor.kt

@@ -1,7 +1,8 @@
+// ALLOW_AST_ACCESS
 package test
 
 enum class En(val b: Boolean = true, val i: Int = 0) {
-    E1: En()
-    E2: En(true, 1)
-    E3: En(i = 2)
+    E1(),
+    E2(true, 1),
+    E3(i = 2)
 }