Turn off creating the modulewrap object files.

Turns this off too when in prepare mode. Appears to be the default
mode on Linux.

Author: dschaefer2

.gitignore

@@ -18,3 +18,4 @@ Package.resolved
 .docc-build
 .vscode
 Utilities/InstalledSwiftPMConfiguration/config.json
+.devcontainer

Sources/Build/BuildManifest/LLBuildManifestBuilder+Swift.swift

@@ -537,7 +537,7 @@ extension LLBuildManifestBuilder {
 
     private func addModuleWrapCmd(_ target: SwiftTargetBuildDescription) throws {
         // Add commands to perform the module wrapping Swift modules when debugging strategy is `modulewrap`.
-        guard target.defaultBuildParameters.debuggingStrategy == .modulewrap else { return }
+        guard target.defaultBuildParameters.debuggingStrategy == .modulewrap, !target.prepareForIndexing else { return }
         var moduleWrapArgs = [
             target.defaultBuildParameters.toolchain.swiftCompilerPath.pathString,
             "-modulewrap", target.moduleOutputPath.pathString,