Link bundled LLVM tools against shared VC runtime to reduce size of VSIX

To address another issue, I've had to link libiconv.dll, and binaries that reference it, against the shared runtime. (libiconv returns results in errno, so it's necessary for the caller to link against the same runtime to access the same errno variable). We already distribute the shared runtime in our 'bin' directory.

It would be possible to link our bundled LLVM tools (clang-tidy, clang-format) to the shared runtime as well. Currently, they are linked statically against the runtime. We'd have to move them into the same 'bin' directory. This could slightly reduce the size of the VSIX.