Add SwiftASN1 to sourcekit-lsp dependencies for Windows.

Updates the build.ps1 script to add the SwiftASN1 package support
to it's CMake build. This was caused by this dependency being added
to a module in SwiftPM that sourcekit-lsp imports.

Author: dschaefer2

utils/build.ps1

@@ -2944,6 +2944,7 @@ function Build-SourceKitLSP([Hashtable] $Platform) {
       TSC_DIR = (Get-ProjectCMakeModules $Platform ToolsSupportCore);
       LLBuild_DIR = (Get-ProjectCMakeModules $Platform LLBuild);
       ArgumentParser_DIR = (Get-ProjectCMakeModules $Platform ArgumentParser);
+      SwiftASN1_DIR = (Get-ProjectCMakeModules $Platform ASN1);
       SwiftCrypto_DIR = (Get-ProjectCMakeModules $Platform Crypto);
       SwiftCollections_DIR = (Get-ProjectCMakeModules $Platform Collections);
       SwiftBuild_DIR = (Get-ProjectCMakeModules $Platform Build);