Inline policy/move logic

[bitfaster]

Before:

Method	Mean	Error	StdDev	Ratio	Gen 0	Allocated
ConcurrentDictionary	16.88 ns	0.276 ns	0.245 ns	1.00	-	-
FastConcurrentLru	23.27 ns	0.491 ns	0.565 ns	1.38	-	-
ConcurrentLru	26.77 ns	0.512 ns	0.666 ns	1.60	-	-
FastConcurrentTLru	54.35 ns	0.650 ns	0.576 ns	3.22	-	-
ConcurrentTLru	60.10 ns	1.024 ns	1.501 ns	3.53	-	-
ClassicLru	68.04 ns	1.400 ns	2.221 ns	4.12	-	-
RuntimeMemoryCache	280.16 ns	5.607 ns	7.486 ns	16.59	0.0153	32 B
ExtensionsMemoryCache	342.72 ns	3.729 ns	3.114 ns	20.29	0.0114	24 B

After

Method	Mean	Error	StdDev	Ratio	Gen 0	Allocated
ConcurrentDictionary	16.76 ns	0.322 ns	0.285 ns	1.00	-	-
FastConcurrentLru	18.94 ns	0.249 ns	0.220 ns	1.13	-	-
ConcurrentLru	21.46 ns	0.204 ns	0.191 ns	1.28	-	-
FastConcurrentTLru	41.57 ns	0.450 ns	0.376 ns	2.48	-	-
ConcurrentTLru	43.95 ns	0.588 ns	0.521 ns	2.62	-	-
ClassicLru	67.62 ns	0.901 ns	0.799 ns	4.03	-	-
RuntimeMemoryCacheGet	279.70 ns	3.825 ns	3.578 ns	16.70	0.0153	32 B
ExtensionsMemoryCacheGet	341.67 ns	6.617 ns	6.499 ns	20.35	0.0114	24 B