Revert^2 "ARM/ARM64: Use introspection marking for JITted code."

This reverts commit 756e722c.

Fix the introspection code to avoid avoid macro instructions
for unpoisoning references inside ExactAssemblyScope.

Change-Id: I6effadb84de74aba0236ab84b52ca85770daf5be
Test: m test-art-host-gtest
Test: Pixel 2 XL boots.
Test: m test-art-target-gtest
Test: testrunner.py --target --optimizing --jit
Test: ART_HEAP_POISONING=true m test-art-target-gtest
Test: ART_HEAP_POISONING=true testrunner.py --target --optimizing --jit
Bug: 36141117