Fix existential-any for Swift6 #333

Job	Run time
test (17.5, 15.4, iPhone 15 Pro, NO, macos-14)	2m 38s
build (5.10, 15.4, macos-14)	30s
test (16.4, 14.3.1, iPhone 14 Pro, NO, macos-13)	5m 10s
cocoapods	1m 5s
build (5.9, 15.2, macos-13)	44s
test (15.5, 13.4.1, iPhone 13 Pro, NO, macos-12)	3m 36s
example (Maps)	1m 12s
build (5.8, 14.3.1, macos-13)	43s
example (Maps-SwiftUI)	55s
build (5.7, 14.1, macos-12)	38s
example (Stocks)	46s
swiftpm (iphoneos, arm64)	17s
build (5.6, 13.4.1, macos-12)	47s
example (Samples)	51s
swiftpm_old (x86_64-apple-ios16.4-simulator, 14.3.1, macos-13)	39s
build (5.5, 13.2.1, macos-12)	2m 42s
swiftpm_old (arm64-apple-ios16.4-simulator, 14.3.1, macos-13)	36s
swiftpm_old (x86_64-apple-ios15.7-simulator, 14.1, macos-12)	43s
swiftpm (iphonesimulator, x86_64)	17s
swiftpm_old (arm64-apple-ios15.7-simulator, 14.1, macos-12)	57s
swiftpm (iphonesimulator, arm64)	19s
	26m 5s

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