Enable LLVM download from CI for gnullvm dist

It no longer fails with an error locally.

Author: mati865

src/ci/docker/host-x86_64/dist-aarch64-windows-gnullvm/Dockerfile

@@ -26,19 +26,10 @@ ENV CC_aarch64_pc_windows_gnullvm=aarch64-w64-mingw32-clang \
 
 ENV HOST=aarch64-pc-windows-gnullvm
 
-# We are bootstrapping this target and cannot use previously built artifacts.
-# Without this option Clang is given `"-I/checkout/obj/build/aarch64-pc-windows-gnullvm/ci-llvm/include"`
-# despite no such directory existing:
-# $ ls obj/dist-windows-gnullvm/build/aarch64-pc-windows-gnullvm/ -1
-# llvm
-# stage2
-ENV NO_DOWNLOAD_CI_LLVM 1
-
 ENV RUST_CONFIGURE_ARGS \
     --enable-full-tools \
     --enable-profiler \
     --enable-sanitizers \
-    --disable-docs \
-    --set llvm.download-ci-llvm=false
+    --disable-docs
 
 ENV SCRIPT python3 ../x.py dist --host $HOST --target $HOST

src/ci/docker/host-x86_64/dist-x86_64-windows-gnullvm/Dockerfile

@@ -28,19 +28,10 @@ ENV CC_i686_pc_windows_gnullvm=i686-w64-mingw32-clang \
 ENV HOST=x86_64-pc-windows-gnullvm
 ENV TARGETS=i686-pc-windows-gnullvm,x86_64-pc-windows-gnullvm
 
-# We are bootstrapping this target and cannot use previously built artifacts.
-# Without this option Clang is given `"-I/checkout/obj/build/aarch64-pc-windows-gnullvm/ci-llvm/include"`
-# despite no such directory existing:
-# $ ls obj/dist-windows-gnullvm/build/aarch64-pc-windows-gnullvm/ -1
-# llvm
-# stage2
-ENV NO_DOWNLOAD_CI_LLVM 1
-
 ENV RUST_CONFIGURE_ARGS \
     --enable-full-tools \
     --enable-profiler \
     --enable-sanitizers \
-    --disable-docs \
-    --set llvm.download-ci-llvm=false
+    --disable-docs
 
 ENV SCRIPT python3 ../x.py dist --host $HOST --target $TARGETS