Fix build with gperf ≥ 3.2

--- src/3rdparty/chromium/third_party/blink/renderer/build/scripts/gperf.py
+++ src/3rdparty/chromium/third_party/blink/renderer/build/scripts/gperf.py
@@ -38,7 +38,7 @@
         # -Wimplicit-fallthrough needs an explicit fallthrough statement,
         # so replace gperf's /*FALLTHROUGH*/ comment with the statement.
         # https://savannah.gnu.org/bugs/index.php?53029
-        gperf_output = gperf_output.replace('/*FALLTHROUGH*/', '  FALLTHROUGH;')
+        #gperf_output = gperf_output.replace('/*FALLTHROUGH*/', '  FALLTHROUGH;')
         script = 'third_party/blink/renderer/build/scripts/gperf.py'
         return '// Generated by %s\n' % script + gperf_output
     except OSError: