This moves several simple StateValuesAccess methods as well as
SparseInputMask::InputIterator::IsReal into their header files so they
can be more easily inlined. This gives about a 7% improvement to the
BackgroundSelectInstructions runtime call stat.

Also marks some methods called by the new methods as V8_PRIVATE_EXPORT
so component build test can build.

Bug: v8:10051
Change-Id: I3e34977a4fa660d3f4f55fd4f2c0b2370d5d2bc2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2023559Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66078}