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x86/x64: Fix math.ceil(-0.9) result sign.

Reported by minoki.

(cherry-picked from commit 674afcd4e)

`ceil` (`floor`) math function implementation calculates (|x| + 2^52) -
2^52 for its argument to determine |x| >= 0.5, so it will be rounded to
nearest integer and its sign is restored. After that if the original
value is < (>), than the result the -1 (1) is substracted from it. Take
a look at the `ceil()` case. The result of the operation `-1 - (-1)` is
+0 for FP arithmetic against -0 expected as a result.

This patch changes the `- (-1)` operation to `+ 1` and restores sign
after it again.

Sergey Kaplun:
* added the description and the test for the problem

Part of tarantool/tarantool#9145

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