[Perf] Display results with 4 significant figures

[mikeharder]

Before

Completed 137,685 operations in a weighted-average of 9.94s (13,846.54 ops/s, 0.000 s/op, 90.69% CPU)

Test	Arguments	12.13.0	source	%Change
download	--size 10240 --parallel 64	14714.67	14540.31	-1.18%
download	--size 10485760 --parallel 32	169.08	167.41	-0.99%
download	--size 10485760 --parallel 32 --sync	175.63	175.52	-0.06%
download	--size 1073741824 --parallel 1 --warmup 60 --duration 60	0.14	0.13	-7.14%
download	--size 1073741824 --parallel 8 --warmup 60 --duration 60	0.82	0.83	1.22%

After

Completed 139,131 operations in a weighted-average of 9.957s (13,973 ops/s, 0.00007157 s/op, 90% CPU)

Test	Arguments	12.13.0	source	%Change
download	--size 10240 --parallel 64	14,712	14,814	0.69%
download	--size 10485760 --parallel 32	167.3	163.8	-2.09%
download	--size 10485760 --parallel 32 --sync	178.0	180.3	1.29%
download	--size 1073741824 --parallel 1 --warmup 60 --duration 60	0.1595	0.1621	1.63%
download	--size 1073741824 --parallel 8 --warmup 60 --duration 60	0.9785	0.9489	-3.03%

Validation Build

https://dev.azure.com/azure-sdk/internal/_build/results?buildId=1743982&view=results

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[mikeharder]

/check-enforcer override