[prebuilt] Update GN to version 547759

Changelog:
8ca5c09bb15f [gn] Updating args --list to emit json
e65dd61a5fea Fix gn bootstrap
c89b8fabf7a9 Fix gn bootstrap
dcba727e7e8b GN: Don't crash when mutating the list in a foreach.
3325da9a7b57 GN: Correct Git Bash removal of leading "/" of "//" labels
36773f30d944 Improved GN code related to resolving paths.
1252d9cdc7a7 gn clean: Don't delete and recreate the build directory.
2caa6c11ddb3 Update GN docs.
6783e46fa01a Correct off-by-one in `Tokenizer::CanIncrement`.
1bcad90daf3d GN: Force normal subprocess task priority on Windows
a3ec9fb724c0 GN: Fix Mac bootstrap compile error
bbc17a396560 GN: Make sure print function flushes stdout to avoid output
delays caused by buffered pipes.
99637d39f360 Remove reference to deleted sequenced_worker_pool
4416579b311c Rename buildflag_header targets in base for consistency
cf54d20bfce0 gn: Write no stamp files for action inputs.
00eba1868282 Fix gn reference in build.ninja after bootstrapping

Change-Id: I39d7a163e8e714f560f6615de4dfb80370efee7d
diff --git a/fuchsia.ensure b/fuchsia.ensure
index fe7c2d1..9d454e4 100644
--- a/fuchsia.ensure
+++ b/fuchsia.ensure
@@ -15,7 +15,7 @@
 infra/ninja/${platform} version:1.8.2
 
 # GN
-infra/tools/gn/${platform} gn_version:535078
+infra/tools/gn/${platform} gn_version:547759
 
 # godepfile
 fuchsia/tools/godepfile/${platform} git_revision:6922d7833617841e853a0be52a285f6cd07a0a10