Remove libc++ from the musl sysroot am: 9f1ffdd3d9 am: 588392e1df

Original change: https://android-review.googlesource.com/c/platform/external/musl/+/2676536

Change-Id: Ie7ad0495a5f9738667be37fbe381b9e97823d81e
Signed-off-by: Automerger Merge Worker <[email protected]>