Previously executConstExpr is called various places, and therefore it was necessary to return interface{}
and that resulted in allocation per call.
This commit avoids the allocation by adding executConstExprI32 which is used by data segment manipulation,
and repurposes executConstExpr solely to global instance initialization.
As a result, this completely removes the allocation around const expr execution, and hence the perf improvement
in the instantiation phrase. The improvement diff is proportionate to the number of data segments and globals.
Signed-off-by: Takeshi Yoneda <takeshi@tetrate.io>
fe8784996c