[clang-format][NFC] Clean up tryToParseLambdaIntroducer()

[curdeius]

LGTM.

clang/lib/Format/UnwrappedLineParser.cpp

do {
     }
   } while (!eof());
 
   // Unreachable for well-formed code (paired '{' and '}').
   return true;
 }
 
 bool UnwrappedLineParser::tryToParseLambda() {
+  assert(FormatTok->is(tok::l_square));
   if (!Style.isCpp()) {
     nextToken();
     return false;
   }
-  assert(FormatTok->is(tok::l_square));
   FormatToken &LSquare = *FormatTok;
   if (!tryToParseLambdaIntroducer())
     return false;
 
   bool SeenArrow = false;
   bool InTemplateParameterList = false;
 
   while (FormatTok->isNot(tok::l_brace)) {
bool UnwrappedLineParser::tryToParseLambda() {
   FormatTok->setFinalizedType(TT_LambdaLBrace);
   LSquare.setFinalizedType(TT_LambdaLSquare);
   parseChildBlock();
   return true;
 }
 
 bool UnwrappedLineParser::tryToParseLambdaIntroducer() {
   const FormatToken *Previous = FormatTok->Previous;
+  const FormatToken *LeftSquare = FormatTok;
+  nextToken();
   if (Previous &&
       (Previous->isOneOf(tok::identifier, tok::kw_operator, tok::kw_new,
                          tok::kw_delete, tok::l_square) ||
-       FormatTok->isCppStructuredBinding(Style) || Previous->closesScope() ||
+       LeftSquare->isCppStructuredBinding(Style) || Previous->closesScope() ||
        Previous->isSimpleTypeSpecifier())) {
-    nextToken();
     return false;
   }
-  nextToken();
   if (FormatTok->is(tok::l_square))
     return false;
   if (FormatTok->is(tok::r_square)) {
     const FormatToken *Next = Tokens->peekNextToken();
-    if (Next && Next->is(tok::greater))
+    if (Next->is(tok::greater))
       return false;
   }
   parseSquare(/*LambdaIntroducer=*/true);
   return true;
 }
 
 void UnwrappedLineParser::tryToParseJSFunction() {
   assert(FormatTok->is(Keywords.kw_function) ||