optimize overflow_check

[johnnychen94]

Even with JuliaLang/julia#37558 fixed, it seems we still need such optimization to minimize the overhead in overflow check.

# Version 1.6.0-DEV.965 (2020-09-18)

julia> a = zeros(5,5,5,5);

# with overflow check (master)
julia> @btime OffsetArray($a, -2:2, -2:2, -2:2, -2:2);
  33.057 ns (0 allocations: 0 bytes)

# with overflow check (this PR)
julia> @btime OffsetArray($a, -2:2, -2:2, -2:2, -2:2);
  16.556 ns (0 allocations: 0 bytes)

# without overflow check
julia> @btime OffsetArray($a, -2:2, -2:2, -2:2, -2:2);
  13.515 ns (0 allocations: 0 bytes)

[codecov]

Codecov Report

Merging #150 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #150   +/-   ##
=======================================
  Coverage   93.60%   93.60%           
=======================================
  Files           2        2           
  Lines         250      250           
=======================================
  Hits          234      234           
  Misses         16       16           

Impacted Files	Coverage Δ
src/OffsetArrays.jl	94.17% <100.00%> (ø)

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