fix CRASH where I delete a pending alarm signal when a 3rd comes in while the pending array is benig processed: * fixed by setting a flag when processing the pending array.   if the flag is set and a new signal comes in, the new one is   dropped instead of dropping an old one, b/c it's not safe to   prepend or delete from the array. * a SIGSEGV while the flag is set is explicitly not dropped so we will   see crashes in that code
fix CRASH where I delete a pending alarm signal when a 3rd comes in while
the pending array is benig processed:
* fixed by setting a flag when processing the pending array.
  if the flag is set and a new signal comes in, the new one is
  dropped instead of dropping an old one, b/c it's not safe to
  prepend or delete from the array.
* a SIGSEGV while the flag is set is explicitly not dropped so we will
  see crashes in that code



git-svn-id: ed337ca7cdb08c0ba29d8fe58632bb7686892c2d@424 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6

rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio