[perf2bolt] Further relax segment matching

Summary:
Previously, we used p_align value of the code segment to predict the
mapping of the segment at runtime. However, at times the reported
value is not aligned and at other times the actual aligned value will
be different because of the different page size used.
All we know is that the page size used at runtime should not exceed
p_align value. Adjust our segment address matching accordingly.

(cherry picked from FBD28133066)