Fix build warnings due to deprecated API usage or unreachable code

Author: jakepetroules

Sources/SwiftDriver/ExplicitModuleBuilds/ExplicitDependencyBuildPlanner.swift

@@ -441,16 +441,7 @@ extension ExplicitDependencyBuildPlanner {
     if let previouslyHashsedName = hashedModuleNameCache[cacheQuery] {
       return previouslyHashsedName
     }
-    let hashedArguments: String
-    #if canImport(Darwin)
-    if #available(macOS 10.15, *) {
-      hashedArguments = CryptoKitSHA256().hash(hashInput).hexadecimalRepresentation
-    } else {
-      hashedArguments = SHA256().hash(hashInput).hexadecimalRepresentation
-    }
-    #else
-    hashedArguments = SHA256().hash(hashInput).hexadecimalRepresentation
-    #endif
+    let hashedArguments = SHA256().hash(hashInput).hexadecimalRepresentation
     let resultingName = moduleName + "-" + hashedArguments
     hashedModuleNameCache[cacheQuery] = resultingName
     return resultingName

Sources/SwiftDriver/IncrementalCompilation/BuildRecordInfo.swift

@@ -112,15 +112,7 @@ import SwiftOptions
       .map { $0.option.spelling }
       .sorted()
       .joined()
-    #if canImport(Darwin)
-    if #available(macOS 10.15, *) {
-      return CryptoKitSHA256().hash(hashInput).hexadecimalRepresentation
-    } else {
-      return SHA256().hash(hashInput).hexadecimalRepresentation
-    }
-    #else
     return SHA256().hash(hashInput).hexadecimalRepresentation
-    #endif
   }
 
   /// Determine the input and output path for the build record

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -4372,9 +4372,7 @@ final class SwiftDriverTests: XCTestCase {
 
   func testVerboseImmediateMode() throws {
     #if os(macOS) && arch(arm64)
-      // Temporarily disabled on Apple Silicon
-      // rdar://80558898
-      throw XCTSkip()
+      try XCTSkipIf(true, "Temporarily disabled on Apple Silicon (rdar://80558898)")
     #endif
 
 // There is nothing particularly macOS-specific about this test other than