Fix space_bitmap_test

This patch is part of the chain preparing for making kPageSize
non-constexpr in a future patch.

space_bitmap_test uses page size as template parameter.
Update the test to access page size as a variable instead.

Test: Same as for I5430741a8494b340ed7fd2d8692c41a59ad9c530.
      The whole patches chain was tested as a whole.
Change-Id: I996275a043621c3a1147e184300e55d57b849d67
1 file changed