CI: Add RV32E test to CI pipeline

Add testing for the RV32E extension to the CI pipeline to ensure automatic
validation during continuous integration.

Author: eleanorLYJ

.ci/riscv-tests.sh

@@ -22,3 +22,4 @@ make ENABLE_EXT_M=1 ENABLE_EXT_A=1 ENABLE_EXT_F=1 ENABLE_EXT_C=1 \
 make arch-test RISCV_DEVICE=IMAFCZicsrZifencei $PARALLEL || exit 1
 make arch-test RISCV_DEVICE=FCZicsr $PARALLEL || exit 1
 make arch-test RISCV_DEVICE=IMZbaZbbZbcZbs $PARALLEL || exit 1
+make distclean && make arch-test RISCV_DEVICE=E $PARALLEL || exit 1