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/psi/secondaryConstructors/enumParsing.kt

@@ -1,7 +1,7 @@
 enum class A {
-   abc1 : A(1,2,3)
-   abc2 : A(1,2,3) {}
-   abc3
+   abc1(1,2,3),
+   abc2(1,2,3) {},
+   abc3;
 
    constructor(x: Int) {}