chore: Add test initializer, eliminate CRT from codegen (#779)

Author: jbelkins

Sources/SmithyTestUtil/TestInitializer.swift

@@ -0,0 +1,15 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import struct AwsCommonRuntimeKit.CommonRuntimeKit
+
+public enum TestInitializer {
+
+    public static func initialize() {
+        CommonRuntimeKit.initialize()
+    }
+}

smithy-swift-codegen/src/main/kotlin/software/amazon/smithy/swift/codegen/PackageManifestGenerator.kt

@@ -77,7 +77,7 @@ class PackageManifestGenerator(val ctx: ProtocolGenerator.GenerationContext) {
             url?.let {
                 writer.write("url: \$S,", it)
             }
-            writer.write("from: \$S", dependency.version)
+            writer.write("exact: \$S", dependency.version)
         }
     }
 

smithy-swift-codegen/src/main/kotlin/software/amazon/smithy/swift/codegen/swiftmodules/AWSCRTTypes.kt

@@ -5,6 +5,7 @@ import software.amazon.smithy.swift.codegen.SwiftDependency
 import software.amazon.smithy.swift.codegen.model.buildSymbol
 
 object SmithyTestUtilTypes {
+    val TestInitializer = runtimeSymbol("TestInitializer")
     val TestBaseError = runtimeSymbol("TestBaseError")
     val SelectNoAuthScheme = runtimeSymbol("SelectNoAuthScheme")
 }