Implement shell-style comments and record shebangs as comments.

pkg/front_end/lib/src/fasta/scanner/utf8_bytes_scanner.dart

Index: pkg/front_end/lib/src/fasta/scanner/utf8_bytes_scanner.dart
diff --git a/pkg/front_end/lib/src/fasta/scanner/utf8_bytes_scanner.dart b/pkg/front_end/lib/src/fasta/scanner/utf8_bytes_scanner.dart
index 98f3293c3d5c86d34b26e730a21e36c3ac522a9a..a2d8925e42b3912740209c51c7744971557a9c03 100644
--- a/pkg/front_end/lib/src/fasta/scanner/utf8_bytes_scanner.dart
+++ b/pkg/front_end/lib/src/fasta/scanner/utf8_bytes_scanner.dart
@@ -86,8 +86,9 @@ class Utf8BytesScanner extends ArrayBasedScanner {
    * array whose last element is '0' to signal the end of the file. If this
    * is not the case, the entire array is copied before scanning.
    */
-  Utf8BytesScanner(this.bytes, {bool includeComments: false})
-      : super(includeComments) {
+  Utf8BytesScanner(this.bytes,
+      {bool includeComments: false, bool enableShellStyleComments: false})
+      : super(includeComments, enableShellStyleComments) {
     assert(bytes.last == 0);
     // Skip a leading BOM.
     if (containsBomAt(0)) byteOffset += 3;