MemSet incorrect copy for native float array with -1

[Cellule]

We used to check if the memset value is -1 to determine if we can do a byte level memset.
This was valid ints but not for floats.
Changed the check to really see if the bytes are all the same.

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This change is

[Cellule]

@LouisLaf @rajatd @pleath Please review

[Cellule]

I realized that there were other occurrences of this bug.
I made a function to gather gather them.
For the double type, I only check for 0 to do a memset as it is unlikely that all byte on a double be the same.
For Var, I don't even bother checking as it will most likely be a pointer or tagged value.
For Integer, I check if the byte are the same aka 0xabababab is valid to do a memset.

[rajatd]

        }

remove this?

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Refers to: lib/Runtime/Library/JavascriptArray.inl:1086 in 4faa24a. [](commit_id = 4faa24a, deletion_comment = False)

[rajatd]