Making the callers responsible for this isn't practical as matrices are
often passed indirectly to a functions such as mat3_to_axis_angle,
BKE_object_mat3_to_rot & BKE_pchan_mat3_to_rot.
Or the matrix is combined from other matrices which could be negative.
Given quaternions calculated from negative matrices are completely
invalid and checking only needs to negate matrices with a negative
determinant, move the check into mat3_to_quat and related functions.
Add mat3_normalized_to_quat_fast for cases no error checking on the
input matrix is needed such as blending rotations.
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