Revert "[Clang] Ignore CLANG_DEFAULT_LINKER for custom-linker toolchains"

Reverted until all Toolchains are fixed for the new behavior.

This reverts commit 34a43f2115af79f896c889433c57f3b400e9f2c6.

GitOrigin-RevId: f6ba6450396ce58212f247c72d84a54efd748b38
4 files changed