[5.7] Improve whereInRaw()

[staudenmeir]

The whereInRaw() method hasn't been released yet, we can still change it:

• Renames it to whereInRawInt() to make its purpose and limitations obvious.
• Removes the array type hint to support Arrayable values. This is consistent with whereIn().
• Replaces array_map() with a foreach loop which is considerably faster. Since the whole point of this method is the performance improvement, we shouldn't waste time here.

Thanks to @vlakoff.

[vlakoff]

Refs #26434 (and #26453).

• Travis CI failures seem to be unrelated.
• I'd rather name it whereInRawInts, let's let Taylor settle for this.

[vlakoff]

Refs the subsequent a3738cf