Fix build warnings about obsolete use of await.

rdar://159492383

Author: mhrawdon

Sources/SWBCore/ToolchainRegistry.swift

@@ -286,7 +286,7 @@ public final class Toolchain: Hashable, Sendable {
             path.join("usr").join("bin"),
         ]
 
-        for platformExtension in await pluginManager.extensions(of: PlatformInfoExtensionPoint.self) {
+        for platformExtension in pluginManager.extensions(of: PlatformInfoExtensionPoint.self) {
             executableSearchPaths.append(contentsOf: platformExtension.additionalToolchainExecutableSearchPaths(toolchainIdentifier: identifier, toolchainPath: path))
         }
 
@@ -450,7 +450,7 @@ public final class ToolchainRegistry: @unchecked Sendable {
             var fs: any FSProxy
         }
 
-        for toolchainExtension in await delegate.pluginManager.extensions(of: ToolchainRegistryExtensionPoint.self) {
+        for toolchainExtension in delegate.pluginManager.extensions(of: ToolchainRegistryExtensionPoint.self) {
             do {
                 for toolchain in try await toolchainExtension.additionalToolchains(context: Context(hostOperatingSystem: hostOperatingSystem, toolchainRegistry: self, fs: fs)) {
                     try register(toolchain)