Add llvm-dwp to LLVM_TOOLCHAIN_TOOLS

since it qualifies as a toolchain tool rather than "internal llvm tool".
This will make it part of builds which set the
LLVM_INSTALL_TOOLCHAIN_ONLY cmake option, such as the Windows installer.

Differential revision: https://reviews.llvm.org/D118042

llvm/cmake/modules/AddLLVM.cmake

@@ -1210,6 +1210,7 @@ if(NOT LLVM_TOOLCHAIN_TOOLS)
     llvm-ar
     llvm-cov
     llvm-cxxfilt
+    llvm-dwp
     llvm-ranlib
     llvm-lib
     llvm-ml