Remove temporary files

Ensure s390x-asm-unsupported-pc-relative-addr and shlibs-cet-support
remove temporary files after a successful execution.

tests/s390x-asm-unsupported-pc-relative-addr/test.sh

@@ -1,8 +1,12 @@
 #!/bin/bash -eux
 
-cd "$(mktemp -d)"
+tmp=$(mktemp -d)
+pushd "$tmp"
 # This asm has an invalid PC relative address.
 echo "start: la %r2,_end-start(%r2)" > test.S
 # clang should fail to build and inform properly about the issue.
 clang -c -o test.o test.S |& tee clang.output ||:
 grep -q "Unsupported PC-relative address" clang.output
+popd
+# On failure, the script will abort and tmp won't be removed.
+rm -rf "$tmp"

tests/shlibs-cet-support/test.sh

@@ -1,9 +1,13 @@
 #!/bin/bash -eux
 
-cd "$(mktemp -d)"
+tmp=$(mktemp -d)
+pushd "$tmp"
 for lib in $(rpm -ql llvm-libs | grep -E '\.so(\..+)?$'); do
     [[ -L $lib ]] && continue # Skip symlinks
     readelf -n "$lib" > notes.log
     grep -q "SHSTK" notes.log
     grep -q "IBT" notes.log
 done
+popd
+# On failure, the script will abort and tmp won't be removed.
+rm -rf "$tmp"