Revert "bp2build: build //system/core/libprocessgroup:libprocess..." am:...

Revert "bp2build: build //system/core/libprocessgroup:libprocess..." am: 1fdd6faf am: 66f3ade5 am: 1f51ec7c am: 2e133bb0

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/1814737

Change-Id: I47acc12f705fdf39e9e2bc2235f683221f09295f