Add initialization of emulation_info to exclude unavoidable DR_ASSERT.

Default initialization produces DR_ASSERT each time because drmgr_get_emulated_instr_data retruns false in this case

        ...
        } else if (drmgr_is_emulation_start(instr)) {
            bool ok = drmgr_get_emulated_instr_data(instr, &emulation_info);
            DR_ASSERT(ok);
        ...

DR_EXPORT
bool
drmgr_get_emulated_instr_data(instr_t *instr, emulated_instr_t *emulated)
{
    ASSERT(instr_is_label(instr), "emulation instruction does not have a label");
    ASSERT(drmgr_is_emulation_start(instr), "instruction is not a start emulation label");

    if (emulated->size < offsetof(emulated_instr_t, flags))
        return false;
   ...