[cxx-interop] Move C++ standard library overlay to the toolchain

The `swiftCxx` and `swiftstd` modules are currently a part of the SDK, but they should be a part of the toolchain instead.

rdar://103082278

Author: egorzhdan

stdlib/public/Cxx/CMakeLists.txt

@@ -15,7 +15,7 @@ add_swift_target_library(swiftCxx ${SWIFT_CXX_LIBRARY_KIND} NO_LINK_NAME IS_STDL
     -Xcc -nostdinc++
 
     LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
-    INSTALL_IN_COMPONENT sdk-overlay
+    INSTALL_IN_COMPONENT compiler
     INSTALL_WITH_SHARED)
 
 add_subdirectory(std)

stdlib/public/Cxx/std/CMakeLists.txt

@@ -147,6 +147,6 @@ add_swift_target_library(swiftstd STATIC NO_LINK_NAME IS_STDLIB
 
     LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
     TARGET_SDKS ALL_APPLE_PLATFORMS LINUX
-    INSTALL_IN_COMPONENT sdk-overlay
+    INSTALL_IN_COMPONENT compiler
     INSTALL_WITH_SHARED
     DEPENDS libstdcxx-modulemap)