Merge "Revert^2 "Remove external/libcxxabi in favor of prebuilt"" into main am: e531c5bd72

Original change: https://android-review.googlesource.com/c/platform/external/libcxxabi/+/3073093

Change-Id: I606f3be212de02523ad0c87e1b2aad109e9b7709
Signed-off-by: Automerger Merge Worker <[email protected]>