Adds recording of all app-valued registers at the skip point of drmemtrace's instrumentation skips for filtered or global-maximum offline trace options. These registers are then restored prior to the skip target, to ensure scratch register parity on all paths.
Tested on the precise basic block that triggered the bug when combined with drreg limitations on which scratch registers to use. Considered trying to create a regression test out of this but there are many complexities that make it non-trivial.
Fixes #4899 (closed)