[CMake] Install SwiftShims when not building stdlib and building tools

Some swift tools will rely on the shims to work properly, but currently they are
only installed if we build the swift stdlib. Like Reflection, we build it if we
are building the tools even if we aren't building the stdlib.

Author: bulbazord

CMakeLists.txt

@@ -1082,6 +1082,7 @@ else()
   # ensure we build that when building tools.
   if(SWIFT_INCLUDE_TOOLS)
     add_subdirectory(stdlib/public/Reflection)
+    add_subdirectory(stdlib/public/SwiftShims)
   endif()
 endif()