Fix parser performance: don't do the additional lookahead when looking for the comma in parameters

compiler/testData/psi/FunctionLiterals_ERR.kt

@@ -18,5 +18,6 @@ fun foo() {
 
     {(a, b) }
     {T.(a, b) }
+    {(a: Int, )}
     {a, }
 }

compiler/testData/psi/FunctionLiterals_ERR.txt

@@ -370,6 +370,30 @@ JetFile: FunctionLiterals_ERR.kt
             <empty list>
           PsiElement(RBRACE)('}')
       PsiWhiteSpace('\n    ')
+      FUNCTION_LITERAL_EXPRESSION
+        FUNCTION_LITERAL
+          PsiElement(LBRACE)('{')
+          VALUE_PARAMETER_LIST
+            PsiElement(LPAR)('(')
+            VALUE_PARAMETER
+              PsiElement(IDENTIFIER)('a')
+              PsiElement(COLON)(':')
+              PsiWhiteSpace(' ')
+              TYPE_REFERENCE
+                USER_TYPE
+                  REFERENCE_EXPRESSION
+                    PsiElement(IDENTIFIER)('Int')
+            PsiElement(COMMA)(',')
+            PsiErrorElement:Expecting a parameter declaration
+              <empty list>
+            PsiWhiteSpace(' ')
+            PsiElement(RPAR)(')')
+          PsiErrorElement:An -> is expected
+            <empty list>
+          BLOCK
+            <empty list>
+          PsiElement(RBRACE)('}')
+      PsiWhiteSpace('\n    ')
       FUNCTION_LITERAL_EXPRESSION
         FUNCTION_LITERAL
           PsiElement(LBRACE)('{')