Remove external/ARMComputeLibrary

This reverts commit 3e98348b8e61e758cbf4c2075fabd1b161cae6a5.

It's still an empty project, it can be re-added if needed again in the future.

Change-Id: I01a21f1dc1f395d8720ce8b99941a6d991b6c210
Test: treehugger
1 file changed