[CI] Disable PIE on Linux Premerge Builds (#154584)

We do not gain any additional security from having PIE on the test
binaries, and this does have an impact on test times. It is about 10%
from my measurements. Not as much as previous reports
(https://reviews.llvm.org/D140880), but still significant. This is a
similar gain to finish enabling the lit internal shell, which will take
significantly more effort. I also do not think this is a meaningful
enough difference from the "default" configuration to keep it the
default, especially given the option is mostly set by distros.

Author: boomanaiden154

.ci/monolithic-linux.sh

@@ -60,7 +60,8 @@ cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
       -D MLIR_ENABLE_BINDINGS_PYTHON=ON \
       -D LLDB_ENABLE_PYTHON=ON \
       -D LLDB_ENFORCE_STRICT_TEST_REQUIREMENTS=ON \
-      -D CMAKE_INSTALL_PREFIX="${INSTALL_DIR}"
+      -D CMAKE_INSTALL_PREFIX="${INSTALL_DIR}" \
+      -D CMAKE_EXE_LINKER_FLAGS="-no-pie"
 
 start-group "ninja"