We'll need one bit in the SharedFunctionInfo::flags to record whether
it's safe to skip arguments adaptor frames (for v8:8895), so this
just removes the SharedFunctionInfo::IsDerivedConstructorBit which is
redundant, since the same information is already available in the
SharedFunctionInfo::FunctionKindBits, and most places in the code
use that already, with the exception of the JSConstructStubGeneric
builtin.

This changes the JSConstructStubGeneric builtin to just check the
function kind instead of testing the explicit bit, which also makes
this more consistent. It seems like there's not much overhead to
that, doing an additional bitmasking plus two comparisons instead
of one. This shouldn't really matter since invocation and execution
of the constructors is going to dominate and optimized code inlines
all of this anyways. If this turns out to affect performance, we
can still look into encoding the FunctionKindBits more cleverly.

Drive-by-fix: Move the FunctionKindBits first in the flags to avoid
the shift when accessing the function kind. This seems logic, since
for the actual boolean bit fields it doesn't matter where they are
in the flags, whereas for the function kind this saves one shift.

Bug: v8:8834, v8:8895
Change-Id: I184a8f5cc5c140bdc272cf9a5ad546093c457306
Reviewed-on: https://chromium-review.googlesource.com/c/1482915Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59821}