Fixes a bug in decode_cti() with a (e)vex prefix with its 2nd or 3rd byte also looking like the first byte of a (e)vex prefix where the instruction is considered invalid, crashing the application.
Adds testing of decode_cti() to api.ir by export decode_cti() in DEBUG and BUILD_TESTS builds. Adds a test case that triggers the observed bug without the fix.
Fixes #3978 (closed)