Add the server RPC executor. (#1715) #1164

Job	Run time
Build and Test on swiftlang/swift:nightly-jammy	4m 26s
Integration Tests on swiftlang/swift:nightly-jammy	3m 24s
Build and Test on swift:5.9-jammy	3m 31s
License Header and Formatting Checks	6m 28s
Performance Tests on swiftlang/swift:nightly-jammy	11m 32s
Integration Tests on swift:5.9-jammy	2m 35s
Build and Test on swift:5.8-focal	3m 24s
Integration Tests on swift:5.8-focal	2m 19s
Build and Test on swift:5.7-focal	3m 12s
Performance Tests on swift:5.9-jammy	10m 9s
Integration Tests on swift:5.7-focal	2m 15s
Performance Tests on swift:5.8-focal	9m 22s
Performance Tests on swift:5.7-focal	9m 29s
	1h 12m 6s

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