Port System.Net.Http benchmarks

[adamsitnik]

Fixes #59

I was not able to run this benchmark with xunit-performance. It uses some certificate files which for some reason were not copied correctly.

BDN results below

Method	ssl	chunkedResponse	responseLength	Mean	Error	StdDev	Median	Min	Max	Allocated
Get	False	False	1	70.17 ms	3.416 ms	3.797 ms	69.06 ms	64.25 ms	77.19 ms	840 B
Get	False	False	100000	324.43 ms	62.427 ms	71.891 ms	291.44 ms	253.76 ms	495.72 ms	840 B
Get	False	True	1	70.68 ms	3.142 ms	3.619 ms	70.23 ms	66.07 ms	78.59 ms	840 B
Get	False	True	100000	307.74 ms	23.810 ms	26.464 ms	304.71 ms	252.37 ms	355.82 ms	840 B
Get	True	False	1	105.34 ms	11.503 ms	13.246 ms	99.22 ms	93.25 ms	136.05 ms	1176 B
Get	True	False	100000	360.92 ms	14.187 ms	14.569 ms	360.44 ms	339.27 ms	399.86 ms	1176 B
Get	True	True	1	122.92 ms	11.790 ms	12.615 ms	125.99 ms	94.29 ms	145.01 ms	1176 B
Get	True	True	100000	370.19 ms	19.658 ms	22.639 ms	370.69 ms	333.84 ms	418.95 ms	1176 B

[jorive]

Have you been able to run these tests on non-Windows platform?

[jorive]