The previous commit d8315e4ed18d introduced a new telemetry field
in the launcher process ping to collect the assembly pattern of
a target function on detour failure, but most of the crash instances
do not have a value in the field. This means the failure happens
before or after `CreateTrampoline`.
To narrow down the root cause, this patch puts a fine-grained error value
in the "hresult" field instead of the hardcoded ERROR_UNIDENTIFIED_ERROR.
This patch also adds `IsPageAccessible` check before fetching data from
a different process because fetching data from an invalid address hits
`MOZ_RELEASE_ASSERT` in `EnsureLimit`, resulting in crash without sending
the launcher process failure.
Differential Revision: https://phabricator.services.mozilla.com/D91881
7034355c29