[Clang] Make download_objdump.py download llvm-bcanalyzer.

This CL adds llvm-bcanalyzer to the list of files packaged and
downloaded by download_objdump.py. This is needed for extracting
data from .o files (which are LLVM Bitcode Files) under LLD-LTO.

Bug: 723798
Change-Id: I87ef05b17399d56f85ca51e042cbc5415edb8bce
Reviewed-on: https://chromium-review.googlesource.com/1106903Reviewed-by: Hans Wennborg <hans@chromium.org>
Reviewed-by: Samuel Huang <huangs@chromium.org>
Commit-Queue: Samuel Huang <huangs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569641}

tools/clang/scripts/package.py

@@ -352,7 +352,8 @@ def main():
   objdumpdir = 'llvmobjdump-' + stamp
   shutil.rmtree(objdumpdir, ignore_errors=True)
   os.makedirs(os.path.join(objdumpdir, 'bin'))
-  for filename in ['llvm-cxxfilt', 'llvm-nm', 'llvm-objdump', 'llvm-readobj']:
+  for filename in ['llvm-bcanalyzer', 'llvm-cxxfilt', 'llvm-nm', 'llvm-objdump',
+                   'llvm-readobj']:
     shutil.copy(os.path.join(LLVM_RELEASE_DIR, 'bin', filename + exe_ext),
                 os.path.join(objdumpdir, 'bin'))
   llvmobjdump_stamp_file_base = 'llvmobjdump_build_revision'