Update fuchsia commit, and SDK to 21.20240610.2.1

This includes a fix to the race when publishing multiple packages at the
same time.

src/ci/docker/host-x86_64/x86_64-gnu-integration/build-fuchsia.sh

@@ -35,7 +35,7 @@ PICK_REFS=()
 # commit hash of fuchsia.git and some other repos in the "monorepo" checkout, in
 # addition to versions of prebuilts. It should be bumped regularly by the
 # Fuchsia team – we aim for every 1-2 months.
-INTEGRATION_SHA=1011e3298775ee7cdf6f6dc73e808d6a86e33bd6
+INTEGRATION_SHA=3284806a4788c4ead8413908026699723dd2ffba
 
 checkout=fuchsia
 jiri=.jiri_root/bin/jiri

src/ci/docker/scripts/build-fuchsia-toolchain.sh

@@ -4,13 +4,13 @@ set -ex
 source shared.sh
 
 FUCHSIA_SDK_URL=https://chrome-infra-packages.appspot.com/dl/fuchsia/sdk/core/linux-amd64
-FUCHSIA_SDK_ID=version:20.20240412.3.1
-FUCHSIA_SDK_SHA256=cc52f3497487dd813c89d9316e6967efcea89c7759edccf3e40fcf3662e53f19
+FUCHSIA_SDK_ID=version:21.20240610.2.1
+FUCHSIA_SDK_SHA256=2d2d057fc3f0404197cced2200f88cbcdaaf5fbf6475955045091f8676791ce7
 FUCHSIA_SDK_USR_DIR=/usr/local/core-linux-amd64-fuchsia-sdk
 CLANG_DOWNLOAD_URL=\
 https://chrome-infra-packages.appspot.com/dl/fuchsia/third_party/clang/linux-amd64
-CLANG_DOWNLOAD_ID=git_revision:c777c011a709dffd4fa5e79cad7947b7c3405d02
-CLANG_DOWNLOAD_SHA256=779167422ad73c292f049dcea5569f84577af9292189ed2749518b966a4d0844
+CLANG_DOWNLOAD_ID=git_revision:3809e20afc68d7d03821f0ec59b928dcf9befbf4
+CLANG_DOWNLOAD_SHA256=3c2c442b61cd9e8f1b567738f6d53cffe11b3fc820e7dae87a82a0859be8f204
 
 install_clang() {
   mkdir -p clang_download

src/ci/docker/scripts/fuchsia-test-runner.py

@@ -286,7 +286,7 @@ def start(self):
         # Look up the product bundle transfer manifest.
         self.log_info("Looking up the product bundle transfer manifest...")
         product_name = "minimal." + self.triple_to_arch(self.target)
-        fuchsia_version = "20.20240412.3.1"
+        fuchsia_version = "21.20240610.2.1"
 
         out = self.check_output(
             [