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/EnumIn.txt

@@ -0,0 +1,21 @@
+JetFile: EnumIn.kt
+  PACKAGE_DIRECTIVE
+    <empty list>
+  IMPORT_LIST
+    <empty list>
+  CLASS
+    MODIFIER_LIST
+      PsiElement(enum)('enum')
+    PsiWhiteSpace(' ')
+    PsiElement(class)('class')
+    PsiWhiteSpace(' ')
+    PsiElement(IDENTIFIER)('Foo')
+    PsiWhiteSpace(' ')
+    CLASS_BODY
+      PsiElement(LBRACE)('{')
+      PsiWhiteSpace('\n    ')
+      ENUM_ENTRY
+        OBJECT_DECLARATION_NAME
+          PsiElement(IDENTIFIER)('`in`')
+      PsiWhiteSpace('\n')
+      PsiElement(RBRACE)('}')