QuickJS: keep reused contexts in their origin queue

QuickJS: keep reused contexts in their origin queue

After an internal redirect, HTTP cleanup selected the destination
location configuration.  If the source and destination used different
module graphs, the source context was inserted into the destination
reuse queue.  A later request could then run a destination handler in
the source runtime, returning an incorrect response or a 500 error.

Record the originating location configuration in each cloned JavaScript
context and use it during teardown.  Source and destination reuse queues
now remain isolated even though internal redirects mutate the request's
current location.