internal/fetch: add runtimesecret and simd goexperiments

For golang/go#21865
For golang/go#71488
For golang/go#73787

Change-Id: Iedb7c007de2ab3840c98b604720f81196a6a6964
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/729900
Reviewed-by: Ethan Lee <ethanalee@google.com>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
kokoro-CI: kokoro <noreply+kokoro@google.com>
diff --git a/internal/fetch/load.go b/internal/fetch/load.go
index 7d9cdde..82667f9 100644
--- a/internal/fetch/load.go
+++ b/internal/fetch/load.go
@@ -439,6 +439,10 @@
 	switch importPath {
 	case "encoding/json/v2", "encoding/json/jsontext":
 		bctx.BuildTags = append(bctx.BuildTags, "goexperiment.jsonv2")
+	case "runtime/secret":
+		bctx.BuildTags = append(bctx.BuildTags, "goexperiment.runtimesecret")
+	case "simd", "simd/archsimd":
+		bctx.BuildTags = append(bctx.BuildTags, "goexperiment.simd")
 	}
 
 	// Copy the input map so we don't modify it.