Rename duplicated swift::fatalError definition in swiftRuntime and swift_Concurrency
Both swiftRuntime and swift_Concurrency had swift::fatalError
implementation, but it causes symbol conflict when -static-stdlib.
This patch renames one of the impl in swift_Concurrency to avoid
conflict.
(cherry picked from commit 709359cfabf9123212b732de2c36c72cf1ef158d)
(cherry picked from commit 9abe6a24edcfecfd9e8ca2c1d8d7844b77c9e434)