This continues our ongoing effort to get a coherent chain of
context.Context all the way from "package main" to all of our calls to
external components.
Context.Import doesn't yet do anything with its new context, but we'll
plumb this deeper in future.
OpenTofu has some historical situational private uses of context.Context
to handle the graceful shutdown behaviors. Those use context.Context as
a private implementation detail rather than public API, and so this commit
leaves them as-is and adds a new "primary context" alongside. Hopefully
in future refactoring we can simplify this to use the primary context also
as the primary cancellation signal, but that's too risky a change to bundle
in with this otherwise-mostly-harmless context plumbing.
All of the _test.go file updates here are purely mechanical additions of
the extra argument. No test is materially modified by this change, which
is intentional to get some assurance that isn't a breaking change.
Signed-off-by: Martin Atkins <mart@degeneration.co.uk>
