Add dump-partial tool.

pkg/front_end/tool/fasta

 #!/bin/bash
 # Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 set -e
 
 REPO_DIR="$(cd ${BASH_SOURCE%/*} && git rev-parse --show-toplevel)"
 
 DART_VM="${REPO_DIR}/sdk/bin/dart"
@@ skipping 19 matching lines @@
     if [ "$#" != "2" ]; then
       stop "Usage: $1 file"
     fi
     ;;
   log) SCRIPT="${TOOL_DIR}/log_analyzer.dart";;
   logd) SCRIPT="${TOOL_DIR}/log_collector.dart";;
   outline) SCRIPT="${TOOL_DIR}/outline.dart";;
   parser) SCRIPT="${TOOL_DIR}/parser.dart";;
   run) SCRIPT="${TOOL_DIR}/run.dart";;
   scanner) SCRIPT="${TOOL_DIR}/scanner.dart";;
+  dump-partial) SCRIPT="${TOOL_DIR}/dump_partial.dart";;
   dump-ir)
     SCRIPT="${KERNEL_BIN}/dump.dart"
     if [ "$#" = "2" ]; then
       # Write to stdout if no target is given.
       set -- "$@" /dev/fd/1
     fi
     if [ "$#" != "3" ]; then
       stop "Usage: $1 dillfile [output]"
     fi
     ;;
@@ skipping 12 matching lines @@
     ;;
   generate-messages) SCRIPT="${TOOL_DIR}/generate_messages.dart";;
   *)
     stop "'$1' isn't a valid subcommand."
     ;;
 esac
 
 shift
 
 exec "${DART_VM}" -c "${SCRIPT}" "$@"