ci: Set ZIG_GLOBAL_CACHE_DIR and ZIG_LOCAL_CACHE_DIR earlier.

Otherwise the disk just keeps getting filled up.

Also remove some pointless cleanup commands since the actions/checkout workflow
step already cleans the repository by default.

ci/x86_64-linux-release.sh

@@ -19,27 +19,24 @@ export PATH="$HOME/deps/wasmtime-v29.0.0-$ARCH-linux:$HOME/deps/qemu-linux-x86_6
 git fetch --unshallow || true
 git fetch --tags
 
-# Test building from source without LLVM.
-git clean -fd
-rm -rf zig-out
-cc -o bootstrap bootstrap.c
-./bootstrap
-./zig2 build -Dno-lib
-./zig-out/bin/zig test test/behavior.zig
-
-export CC="$ZIG cc -target $TARGET -mcpu=$MCPU"
-export CXX="$ZIG c++ -target $TARGET -mcpu=$MCPU"
-
-rm -rf build-release
-mkdir build-release
-cd build-release
-
 # Override the cache directories because they won't actually help other CI runs
 # which will be testing alternate versions of zig, and ultimately would just
 # fill up space on the hard drive for no reason.
 export ZIG_GLOBAL_CACHE_DIR="$PWD/zig-global-cache"
 export ZIG_LOCAL_CACHE_DIR="$PWD/zig-local-cache"
 
+# Test building from source without LLVM.
+cc -o bootstrap bootstrap.c
+./bootstrap
+./zig2 build -Dno-lib
+./zig-out/bin/zig test test/behavior.zig
+
+mkdir build-release
+cd build-release
+
+export CC="$ZIG cc -target $TARGET -mcpu=$MCPU"
+export CXX="$ZIG c++ -target $TARGET -mcpu=$MCPU"
+
 cmake .. \
   -DCMAKE_INSTALL_PREFIX="stage3-release" \
   -DCMAKE_PREFIX_PATH="$PREFIX" \
@@ -92,12 +89,9 @@ diff stage3-release/bin/zig stage4-release/bin/zig
 # Ensure that updating the wasm binary from this commit will result in a viable build.
 stage3-release/bin/zig build update-zig1
 
-rm -rf ../build-new
 mkdir ../build-new
 cd ../build-new
 
-export ZIG_GLOBAL_CACHE_DIR="$PWD/zig-global-cache"
-export ZIG_LOCAL_CACHE_DIR="$PWD/zig-local-cache"
 export CC="$ZIG cc -target $TARGET -mcpu=$MCPU"
 export CXX="$ZIG c++ -target $TARGET -mcpu=$MCPU"