Update gvisor and bump to go1.27 (#1940)

gvisor's arm64 race-build compare-and-swap (pkg/sync/race_arm64.s)
loaded the new value into the register meant for the old one (R1
instead of R2), so it never succeeded. Sleepers could not commit to
parking and spun: under -race on arm64 every idle service netstack
busied about 14 cores, and TestService's static host lookup of
localhost missed its 250ms timeout and stalled for the 30s static_map
cadence. Fixed in gvisor 1b2946c4fa.

Go 1.27.2 is now the minimum because gvisor's go branch requires it.
golangci-lint is bumped to v2.14, the first release that can read
go1.27.2 export data.

.github/workflows/smoke.yml

@@ -22,7 +22,7 @@ jobs:
 
     - uses: actions/setup-go@v7
       with:
-        go-version: '1.26'
+        go-version: '1.27'
         check-latest: true
 
     - name: Smoke Docker
@@ -51,7 +51,7 @@ jobs:
 
     - uses: actions/setup-go@v7
       with:
-        go-version: '1.26'
+        go-version: '1.27'
         check-latest: true
 
     - name: build