Hubert Tong
77b12913a0
Test detection, during stepping, of the backchain mutation introduced by a VAPI call (see https://github.com/llvm/llvm-project/pull/209280). Further, test resumption of contexts using cursors obtained while a VAPI is active on the thread. Testing is done via FileCheck inspection of trace output enabled by `LIBUNWIND_PRINT_UNWINDING=1`. When Live Library Update is not enabled, synthetic trace output is generated by the test program itself. --------- Assisted-by: IBM Bob (cherry picked from commit 861efe03d96d93cd7e475d15bbc676f6d521f4fd)