config: revamp x86 config to avoid appending to SimObjectVectors

config: revamp x86 config to avoid appending to SimObjectVectors
A significant contributor to the need for adoptOrphanParams()
is the practice of appending to SimObjectVectors which have
already been assigned as children.  This practice sidesteps the
assignment operation for those appended SimObjects, which is
where parent/child relationships are typically established.

This patch reworks the config scripts that use append() on
SimObjectVectors, which all happen to be in the x86 system
configuration.  At some point in the future, I hope to make
SimObjectVectors immutable (by deriving from tuple rather than
list), at which time this patch will be necessary for correct
operation.  For now, it just avoids some of the warning
messages that get printed in adoptOrphanParams().