Revert "Revert "Revert "Adapt scheduler to work with dynamic derivations"""

The bug reappeared after all, and the fix introduced a different bug. I
just reverted on 2.27 first, in #12576, but upon further introspection
and discussion with @roberth, with preparing for and travelling to
Planet Nix I will not be able to fix it on `master` soon enough for a
revert to not be warranted here in the meantime also.

This reverts commit c98525235f.

tests/functional/dyn-drv/build-built-drv.sh

@@ -18,9 +18,4 @@ clearStore
 
 drvDep=$(nix-instantiate ./text-hashed-output.nix -A producingDrv)
 
-# Store layer needs bugfix
-requireDaemonNewerThan "2.27pre20250205"
-
-out2=$(nix build "${drvDep}^out^out" --no-link)
-
-test $out1 == $out2
+expectStderr 1 nix build "${drvDep}^out^out" --no-link | grepQuiet "Building dynamic derivations in one shot is not yet implemented"

tests/functional/dyn-drv/dep-built-drv-2.sh

@@ -13,4 +13,4 @@ restartDaemon
 NIX_BIN_DIR="$(dirname "$(type -p nix)")"
 export NIX_BIN_DIR
 
-nix build -L --file ./non-trivial.nix --no-link
+expectStderr 1 nix build -L --file ./non-trivial.nix --no-link | grepQuiet "Building dynamic derivations in one shot is not yet implemented"

tests/functional/dyn-drv/dep-built-drv.sh

@@ -4,11 +4,8 @@ source common.sh
 
 out1=$(nix-build ./text-hashed-output.nix -A hello --no-out-link)
 
-# Store layer needs bugfix
-requireDaemonNewerThan "2.27pre20250205"
-
 clearStore
 
-out2=$(nix-build ./text-hashed-output.nix -A wrapper --no-out-link)
+expectStderr 1 nix-build ./text-hashed-output.nix -A wrapper --no-out-link | grepQuiet "Building dynamic derivations in one shot is not yet implemented"
 
-diff -r $out1 $out2
+# diff -r $out1 $out2

tests/functional/dyn-drv/failing-outer.sh

@@ -5,6 +5,8 @@ source common.sh
 # Store layer needs bugfix
 requireDaemonNewerThan "2.27pre20250205"
 
+skipTest "dyn drv input scheduling had to be reverted for 2.27"
+
 expected=100
 if [[ -v NIX_DAEMON_PACKAGE ]]; then expected=1; fi # work around the daemon not returning a 100 status correctly