[build-windows-toolchain] Fix SwiftSyntax dependency

Author: stevapple

utils/build-windows-toolchain.bat

@@ -219,6 +219,7 @@ cmake ^
   -D PYTHON_HOME=%PYTHON_HOME% ^
   -D PYTHON_EXECUTABLE=%PYTHON_HOME%\python.exe ^
   -D SWIFT_PATH_TO_LIBDISPATCH_SOURCE="%SourceRoot%\swift-corelibs-libdispatch" ^
+  -D SWIFT_PATH_TO_SWIFT_SYNTAX_SOURCE="%SourceRoot%\swift-syntax" ^
   -D EXPERIMENTAL_STRING_PROCESSING_SOURCE_DIR=%SourceRoot%\swift-experimental-string-processing ^
 
   -G Ninja ^
@@ -246,6 +247,7 @@ cmake ^
   -D LLVM_DIR=%BuildRoot%\1\lib\cmake\llvm ^
   -D SWIFT_NATIVE_SWIFT_TOOLS_PATH=%BuildRoot%\1\bin ^
   -D SWIFT_PATH_TO_LIBDISPATCH_SOURCE=%SourceRoot%\swift-corelibs-libdispatch ^
+  -D SWIFT_PATH_TO_SWIFT_SYNTAX_SOURCE="%SourceRoot%\swift-syntax" ^
   -D EXPERIMENTAL_STRING_PROCESSING_SOURCE_DIR=%SourceRoot%\swift-experimental-string-processing ^
 
   -D SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY=YES ^