Add implicit cast for 'sum' and 'count' #5112

Job	Run time
clang-format	1m 3s
build_test (LLVM 10 Release, Release, .#bpftrace-llvm10, tcpdrop.bt, biosnoop.bt)	11m 13s
build_test (LLVM 11 Release, Release, .#bpftrace-llvm11, tcpdrop.bt, biosnoop.bt)	11m 39s
build_test (LLVM 12 Release, Release, .#bpftrace-llvm12, tcpdrop.bt, biosnoop.bt)	12m 0s
build_test (LLVM 13 Release, Release, .#bpftrace-llvm13, tcpdrop.bt, biosnoop.bt)	11m 34s
build_test (LLVM 14 Release, Release, .#bpftrace-llvm14, tcpdrop.bt, biosnoop.bt)	11m 32s
build_test (LLVM 15 Release, Release, .#bpftrace-llvm15, tcpdrop.bt, biosnoop.bt)	13m 23s
build_test (LLVM 16 Release, Release, .#bpftrace-llvm16, tcpdrop.bt, biosnoop.bt)	11m 29s
build_test (LLVM 17 Release, Release, .#bpftrace-llvm17, tcpdrop.bt, biosnoop.bt)	11m 28s
build_test (LLVM 17 Debug, Debug, .#bpftrace-llvm17, tcpdrop.bt, biosnoop.bt)	14m 0s
build_test (LLVM 17 Clang Debug, Debug, .#bpftrace-llvm17, clang, clang++, tcpdrop.bt, biosnoop.bt)	11m 49s
build_test (Memleak test (LLVM 11 Debug), Debug, .#bpftrace-llvm11, 1, 0)	7m 11s
build_test (Memleak test (LLVM 11 Release), Release, .#bpftrace-llvm11, 1, 0)	5m 31s
irc	0s
	2h 13m 52s

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