Stop parsing lambdas with deprecated syntax

compiler/testData/psi/examples/util/Comparison.kt

@@ -10,7 +10,7 @@ enum class ComparisonResult {
 
 typealias MatchableComparison<in T> =  (T, T) -> ComparisonResult
 
-fun asMatchableComparison<T>(cmp : Comparison<T>) : MatchableComparison<T> = {(a, b) ->
+fun asMatchableComparison<T>(cmp : Comparison<T>) : MatchableComparison<T> = {a, b ->
   val res = cmp(a, b)
   if (res == 0) return ComparisonResult.EQ
   if (res < 0) return ComparisonResult.LS

compiler/testData/psi/examples/util/Comparison.txt

@@ -324,14 +324,12 @@ JetFile: Comparison.kt
       FUNCTION_LITERAL
         PsiElement(LBRACE)('{')
         VALUE_PARAMETER_LIST
-          PsiElement(LPAR)('(')
           VALUE_PARAMETER
             PsiElement(IDENTIFIER)('a')
           PsiElement(COMMA)(',')
           PsiWhiteSpace(' ')
           VALUE_PARAMETER
             PsiElement(IDENTIFIER)('b')
-          PsiElement(RPAR)(')')
         PsiWhiteSpace(' ')
         PsiElement(ARROW)('->')
         PsiWhiteSpace('\n  ')