drraw2trace maps vdso twice but never references the second

For #3900 (closed) we split the vdso into two separate segments. But drraw2trace re-maps the full stored vdso for the 2nd, despite translating 2nd-page addresses to the first segment:

[drmemtrace]: Using module 11 [vdso] stored 8192-byte contents @0x55d569b449ef
[drmemtrace]: Using module 12 [vdso] stored 8192-byte contents @0x55d569b46a58
Mapped vdso1+0x10 to 55d569b449ff; range 55d569b449ef size 2000
Mapped vdso2+0x10 to 55d569b459ff; range 55d569b449ef size 2000