Exports the DR_NOTE_ANNOTATION label identifier and has drreg look for it to treat an annotation label as a read of all register values.
Augments the annotation-detection full-decode tests to use drreg to clobber all annotation parameter registers. This causes test failure without the drreg fix added here.
Also tested on Dr. Memory's 32-bit mmap test (with a near-identical check in Dr. Memory's register spill code to what is here for drreg), which fails without this fix.
Fixes #5118 (closed)