Remove Instrumentation::can_use_instrumentation_trampolines_.

And cleanup how deopt_manager notifies how to do single thread deopt by
using an instrumentation key.

can_use_instrumentation_trampolines_ seems to have been used as a
workaround for an issue that doesn't manifest anymore after the cleanup.

Test: test.py
Change-Id: I6e34ef01c502a158f0a403e755c525f33bfa3ca9
4 files changed