fix Issue 13827 - Internal Compiler Error: null field
fix Issue 13831 - DMD crash on newing struct with overlapped fields in CTFE
fix Issue 13841 - infinite loop in compiler on simd arithmetic
Merge pull request #4206 from 9rnsr/fix13841

Issue 13841 - infinite loop in compiler on simd arithmetic
Merge pull request #4204 from 9rnsr/fix13827

[REG2.067a] Issue 13827 - Internal Compiler Error: null field
Merge pull request #4205 from 9rnsr/fix13831

Issue 13831 - DMD crash on newing struct with overlapped fields in CTFE