scripts/run_test: Use grep -E instead of egrep

Grep in Fedora 39 has started warning when invoked as 'egrep',
so use grep -E instead to avoid the warnings.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

scripts/run_test.sh

@@ -21,7 +21,7 @@ cd $TMPDIR
 
 cp ${MICROWATT_DIR}/tests/${TEST}.bin main_ram.bin
 
-${MICROWATT_DIR}/core_tb | sed 's/.*: //' | egrep '^(GPR[0-9]|LR |CTR |XER |CR [0-9])' | sort | grep -v GPR31 > test.out || true
+${MICROWATT_DIR}/core_tb | sed 's/.*: //' | grep -E '^(GPR[0-9]|LR |CTR |XER |CR [0-9])' | sort | grep -v GPR31 > test.out || true
 
 grep -v "^$" ${MICROWATT_DIR}/tests/${TEST}.out | sort | grep -v GPR31 > exp.out