[libFuzzer] use pkill instead of killall in a test since the bots don't have killall
@@ -19,7 +19,7 @@ RUN: echo g > %t/C2/g
RUN: %t/LFSIGUSR -merge=1 -merge_control_file=%t/MCF %t/C1 %t/C2 2> %t/log & export PID=$!
RUN: sleep 3
-RUN: killall -SIGUSR2 %t/LFSIGUSR
+RUN: pkill -f -SIGUSR2 %t/LFSIGUSR
RUN: cat %t/log | FileCheck %s
RUN: grep C2/g %t/MCF
RUN: grep STARTED %t/MCF
