Reland(2): "Enable the fast package installation method by default"

This is a reland of commit aad18e188e6c315e79c3cd9f77b3821c5619da87

b/300130101 should have been fixed by earlier changes in the stack.

Original change's description:
> Reland "Enable the fast package installation method by default"
>
> This is a reland of commit 408001e5e8016218bd89ca439b410f5ea0310ebb
>
> We've fixed b/300130101.
>
> Original change's description:
> > Enable the fast package installation method by default
> >
> > BUG=b:280673549
> > TEST=BOARD=amd64-generic bazel build @portage//sys-apps/attr
> >
> > Change-Id: I78498c72e5c02a4d5a0821fef0a1fba1313c7630
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/bazel/+/4855872
> > Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
> > Commit-Queue: Shuhei Takahashi <nya@chromium.org>
> > Tested-by: Shuhei Takahashi <nya@chromium.org>
>
> BUG=b:280673549
> BUG=b:300130101
>
> Change-Id: I6e7a65c418ecc10100204c46d3b0e56a48311eda
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/bazel/+/4878897
> Auto-Submit: Shuhei Takahashi <nya@chromium.org>
> Tested-by: Shuhei Takahashi <nya@chromium.org>
> Commit-Queue: Ryo Hashimoto <hashimoto@chromium.org>
> Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>

BUG=b:280673549
BUG=b:300130101

Cq-Depend: chromium:4896616
Cq-Depend: chromium:4898078
Change-Id: Iab8d9ca06d9211fcf803ce339c3a995dc72c04be
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/bazel/+/4896618
Tested-by: Shuhei Takahashi <nya@chromium.org>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Commit-Queue: Shuhei Takahashi <nya@chromium.org>
diff --git a/portage/bin/alchemist/src/bin/alchemist/generate_repo/templates/root.BUILD.bazel b/portage/bin/alchemist/src/bin/alchemist/generate_repo/templates/root.BUILD.bazel
index df95f4e..7810499 100644
--- a/portage/bin/alchemist/src/bin/alchemist/generate_repo/templates/root.BUILD.bazel
+++ b/portage/bin/alchemist/src/bin/alchemist/generate_repo/templates/root.BUILD.bazel
@@ -13,7 +13,7 @@
 
 string_flag(
     name = "binpkg-cache-strategy",
-    build_setting_default = "naive",
+    build_setting_default = "fast",
     values = ["fast", "naive", "slow"],
 )
 
diff --git a/portage/bin/alchemist/src/bin/alchemist/testdata/golden/BUILD.golden.bazel b/portage/bin/alchemist/src/bin/alchemist/testdata/golden/BUILD.golden.bazel
index df95f4e..7810499 100644
--- a/portage/bin/alchemist/src/bin/alchemist/testdata/golden/BUILD.golden.bazel
+++ b/portage/bin/alchemist/src/bin/alchemist/testdata/golden/BUILD.golden.bazel
@@ -13,7 +13,7 @@
 
 string_flag(
     name = "binpkg-cache-strategy",
-    build_setting_default = "naive",
+    build_setting_default = "fast",
     values = ["fast", "naive", "slow"],
 )