[lldb][FreeBSDKernel] Add missing error checks in DynamicLoader (#189250)
Add extra guards in case a call to function fails. For example, the
result of `ReadMemory()` cannot be trusted when `error.Fail()` is true,
and this change ensures the code executes properly according to the
value of the error.
Signed-off-by: Minsoo Choo <minsoochoo0122@proton.me>