[PERF2BOLT] Fix unittest failure

Fix failure caused by commit e549ac072b "Do not issue parsing error on
weird build ids".

bolt/include/bolt/Profile/DataAggregator.h

@@ -311,6 +311,10 @@ private:
   /// Consume the entire line
   void consumeRestOfLine();
 
+  /// True if the next token in the parsing buffer is a new line, but don't
+  /// consume it (peek only).
+  bool checkNewLine();
+
   /// Parse a single LBR entry as output by perf script -Fbrstack
   ErrorOr<LBREntry> parseLBREntry();
 

bolt/lib/Profile/DataAggregator.cpp

@@ -1056,6 +1056,10 @@ void DataAggregator::consumeRestOfLine() {
   Line += 1;
 }
 
+bool DataAggregator::checkNewLine() {
+  return ParsingBuf[0] == '\n';
+}
+
 ErrorOr<DataAggregator::PerfBranchSample> DataAggregator::parseBranchSample() {
   PerfBranchSample Res;
 
@@ -2148,7 +2152,7 @@ DataAggregator::parseNameBuildIDPair() {
   // If one of the strings is missing, don't issue a parsing error, but still
   // do not return a value.
   consumeAllRemainingFS();
-  if (checkAndConsumeNewLine())
+  if (checkNewLine())
     return NoneType();
 
   ErrorOr<StringRef> NameStr = parseString(FieldSeparator, true);