Revert "Switch to Metalava to generate libcore docs"

Bug: b/70351683 b/78245848

This reverts commit 3e70a825960bf360279f750e1c2001b3fd789f07.

Reason for revert: Breaks robolectric tests

Change-Id: Ie42c06d45560616ebf44754f3ea198639da38282
1 file changed