[Refactoring] for StructDeclaration::buildCpCtor
Add loc for internal generated code

For:
1. Avoid "no line number" issues
2. For the DDMD automatic code translation to D
Move test case for issue 10053 to runnable/sdtor.d

Collecting tests for struct destructor into same file is useful.
fix Issue 10055 - Incorrect attribute merging in dtor/postblit building
Merge pull request #2006 from 9rnsr/fix10055

[REG2.063a] Issue 10055 - Incorrect attribute merging in dtor/postblit building