qe-wasm: Fix consistent `now()` value (#4650)
* qe-wasm: Fix consistent `now()` value
We implemented introduced consitent `request_now` value in #3200,
however, we've opted out of thread local value if there is no active
tokio handle. This is problem for WASM build, since it does not have
use an actual tokio runtime.
Replacing handle check with `LocalKey::try_with` allows us to use task
local variable without the runtime, while still preserving fallback for
immediate value if task local is not set.
Fix prisma/team-orm#645
* Fix formatting
* Reword comment
