APPCRASH (r2718) ia32.optdebug build of Chrome's test driver "d8" crashes with NULL pointer in debug DR

_From [byron.c....@gmail.com](https://code.google.com/u/101184679827294438523/) on July 12, 2014 04:04:36_

Running any of the javascript tests in the ia32.optdebug build of d8 in debug dynamorio always crashes with a NULL pointer at the same instruction:

08737f30 <_ZN2v88internal13AssemblerBaseD1Ev>:
8737f30: 83 ec 1c sub $0x1c,%esp
8737f33: 89 5c 24 14 mov %ebx,0x14(%esp)
8737f37: 8b 5c 24 20 mov 0x20(%esp),%ebx
8737f3b: 89 74 24 18 mov %esi,0x18(%esp)
8737f3f: 80 7b 0c 00 cmpb $0x0,0xc(%ebx) # segfault: %ebx == NULL

0xf72adc06
0xf72aefb6
0xf72a756b
0xf72ac1a8
0xf72a9894
0xf72abe94
0xf7275120
>

No problems with the release build of DR, and the plain ia32.debug build of d8 works in debug DR.

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=1471_