Revert memory mapped coverage

Bug: http://b/194128476
Bug: http://b/210012154

Reverts:
e6840726 "[coverage] Override -Wframe-larger-than"
71d697c5 "Enable memory-mapped coverage instrumentation"

Coverage metrics dropped for ~10 of the 40 modules.  There are also
regressions in mainline when running tests on older platform builds.

Test: presubmit
Change-Id: I4a2b005d3b54764b762b5422e03b7a9ec8727227