Removes a requirement for an aligned target when encoding without checking reachability, to allow a branch to a label whose note is set to a small integer during instrumentation.
Removes a debug warning about an encoding failure for !assert_reachable for the same reason: a branch to a label with a small note value.
Adds a regression test case to api.ir. Confirmed that it fails without these fixes.
Fixes #5297 (closed)