Don't change timestamps in update_font_metadata

This causes non-reproducable builds.

Bug: 307824623
Test: ./build/soong/tests/genrule_sandbox_test.py UpdatableSystemFontTest_NotoColorEmojiV0.ttf
Change-Id: I2f055740f44153a85fad6040d825c2e80bf2e77d
diff --git a/tools/fonts/update_font_metadata.py b/tools/fonts/update_font_metadata.py
index c07a98a..04a5528 100755
--- a/tools/fonts/update_font_metadata.py
+++ b/tools/fonts/update_font_metadata.py
@@ -19,7 +19,7 @@
     args_parser.add_argument('--revision', help='Updated font revision. Use + to update revision based on the current revision')
     args = args_parser.parse_args()
 
-    font = ttLib.TTFont(args.input)
+    font = ttLib.TTFont(args.input, recalcTimestamp=False)
     update_font_revision(font, args.revision)
     font.save(args.output)