Add IBC support (dotnet/coreclr#19046)

Add IBC support (dotnet/coreclr#19046)

This change adds support to consume IBC data packages that are created by the dotnet/optimization repository. With these changes and dotnet/buildtoolsdotnet/coreclr#2103 to enable IBC optimizations for corefx, we will see a 32% decrease in the size of NetCoreApp (and an overall decrease of 16%), a 30% reduction in ref set, a 5% improvement in time to first request and steady state performance for MusicStore.

Size

 	Crossgen	Partial	Partial vs Crossgen (lower is better)
Shared (MB)	185.6	137.3	0.74
Microsoft.NETCore.App (MB)	115.6	67.4	0.58
RefSet

MusicStore

 	Crossgen	Partial	Partial vs Crossgen (lower is better)
Total	19.389	13.472	0.69
AllReady

Crossgen	Partial	Partial vs Crossgen (lower is better)
Total	17.58	12.214
Performance

MusicStore

 	Crossgen	Partial	Partial vs Crossgen (lower is better)
Server Start (ms)	870	870.6	1.00
First request (ms)	3532.6	3386.6	0.95
Steady State (ms)	2.926	2.79	0.95
AllReady

Crossgen	Partial	Partial vs Crossgen (lower is better)
Server Start (ms)	2102	1942.4
First Request (ms)	4263.2	4126
Steady State (ms)	5.69	5.68
TechEmpower Plaintext

Crossgen	Partial	Partial vs Crossgen (lower is better)
Requests per Second	1928649.8	1893183.8
First Request (ms)	76.14	80.11
Startup (ms)	391	372.8
Working Set (MB)	382.2	373.4

Commit migrated from https://github.com/dotnet/coreclr/commit/e30616f7810838f94170786d9477df2423f4fa09