[math] Add missing includes required for std::copy.

[hageboeck]

std::copy stopped to compile on Mac beta, unless <algorithm> is included.

In doing that, clangd claimed that <iostream> is unnecessary in FitData.h, so I removed it.

For reference, #21311 failed with:

  [ 56%] Generating G__ROOTHist.cxx, ../../lib/ROOTHist.pcm
  In file included from input_line_10:10:
  In file included from /Users/sftnight/ROOT-CI/build/include/Fit/BinData.h:16:
  /Users/sftnight/ROOT-CI/build/include/Fit/FitData.h:346:21: error: no member named 'copy' in namespace 'std'
                 std::copy(fCoordsPtr[i], fCoordsPtr[i] + fNPoints + padding, fCoords[i].begin());
                 ~~~~~^
  Error: /Users/sftnight/ROOT-CI/build/bin/rootcling: compilation failure (/Users/sftnight/ROOT-CI/build/lib/libMathCoref28027eebe_dictUmbrella.h)
  make[2]: *** [math/mathcore/G__MathCore.cxx] Error 1
  make[1]: *** [math/mathcore/CMakeFiles/G__MathCore.dir/all] Error 2
  make[1]: *** Waiting for unfinished jobs....

Edit:
Same error for GSLSimAnnealing.h, checking for more problems.

[guitargeek]

Thanks!

[github-actions]

Test Results

    22 files      22 suites   3d 5h 51m 15s ⏱️
 3 793 tests  3 789 ✅ 0 💤 4 ❌
75 413 runs  75 409 ✅ 0 💤 4 ❌

For more details on these failures, see this check.

Results for commit 2cb47f7.

[bellenot]

Thanks Stephan!

[hageboeck]

Things are compiling again on mac beta, but we need to find the source of the test failures next.