ci: skip setup-go cache on self-hosted runners (#11985)

* ci: skip setup-go cache on self-hosted runners

The module cache is already local on a persistent self-hosted runner;
archiving ~/go/pkg/mod into cache.tzst at every job's end is pure cost
and can stall (a ~4-minute zstdmt hang was observed on awscli-tests).
runner.environment gates the cache to GitHub-hosted runners only.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* ci: gate the remaining setup-go caches too

The first pass only covered go-version-file steps; go-version steps in
nine workflows (including awscli-tests' own file) kept uploading the
cache archive on self-hosted runners.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

.github/workflows/go.yml

@@ -35,6 +35,7 @@ jobs:
       uses: actions/setup-go@v7
       with:
         go-version-file: 'go.mod'
+        cache: ${{ runner.environment == 'github-hosted' }}
     - name: Get dependencies
       run: |
         cd weed; go get -v -t -d ./...
@@ -57,6 +58,7 @@ jobs:
       uses: actions/setup-go@v7
       with:
         go-version-file: 'go.mod'
+        cache: ${{ runner.environment == 'github-hosted' }}
     - name: Go Vet linux/386 (type-checks code and tests for 32-bit int overflows)
       run: |
         GOOS=linux GOARCH=386 go vet ./... 2>&1 | grep -v "MessageState contains sync.Mutex" | grep -v "IdentityAccessManagement contains sync.RWMutex" | tee vet-32bit-output.txt
@@ -72,6 +74,7 @@ jobs:
       uses: actions/setup-go@v7
       with:
         go-version-file: 'go.mod'
+        cache: ${{ runner.environment == 'github-hosted' }}
     - name: Build
       run: cd weed; go build -tags "elastic gocdk sqlite ydb tarantool tikv rclone" -v .
 
@@ -94,6 +97,7 @@ jobs:
       uses: actions/setup-go@v7
       with:
         go-version-file: 'go.mod'
+        cache: ${{ runner.environment == 'github-hosted' }}
     # Nothing else on a PR compiles these, so per-OS syscall constants creep
     # back into shared files unnoticed and only a release build catches it.
     - name: Cross-compile
@@ -128,6 +132,7 @@ jobs:
       uses: actions/setup-go@v7
       with:
         go-version-file: 'go.mod'
+        cache: ${{ runner.environment == 'github-hosted' }}
     - name: Test
       env:
         RUN_REDIS_TESTS: "1"
@@ -143,6 +148,7 @@ jobs:
       uses: actions/setup-go@v7
       with:
         go-version-file: 'go.mod'
+        cache: ${{ runner.environment == 'github-hosted' }}
     # 386 test binaries run natively on the amd64 runner. This catches what vet
     # can't: unaligned 64-bit atomics and arithmetic that wraps at runtime.
     # -short skips the e2e suites already covered on amd64.
@@ -159,6 +165,7 @@ jobs:
       uses: actions/setup-go@v7
       with:
         go-version-file: 'go.mod'
+        cache: ${{ runner.environment == 'github-hosted' }}
     # weed/kms/azure is excluded from every default build, so without this
     # nothing compiles it and tag-gated code silently rots.
     - name: Build and test with azurekms