update_prebuilts.py: make contents of lld-bin executable

Python's ZipFile.extractall strips the executable bits from the
permissions.  update_prebuilts.py restores the executable bits for
the files it moves into the bin directory, but that doesn't cover the
lld-bin directory.  Manually mark any files in the lld-bin directory
executable.

Bug: 180055535
Test: ./update_prebuilts.py -b 6752562
Change-Id: I40a2a1c479ada224dbbe0b662779594f6094839c
diff --git a/update_prebuilts/update_prebuilts.py b/update_prebuilts/update_prebuilts.py
index 4019e2d..47f9bcf 100755
--- a/update_prebuilts/update_prebuilts.py
+++ b/update_prebuilts/update_prebuilts.py
@@ -588,6 +588,11 @@
         mv(src_file, dst_file)
         os.chmod(dst_file, 0o755)
 
+    # Make the files under lld-bin executable
+    lld_bin_files = os.listdir(os.path.join(dst_path, 'lld-bin'))
+    for file in lld_bin_files:
+        os.chmod(os.path.join(dst_path, 'lld-bin', file), 0o755)
+
     # Remove renderscript
     rm(path(dst_path, 'renderscript'))