[yaml2obj] - Change the order of implicitly created sections.

.dynsym and .dynstr are allocatable and therefore normally are placed
before non-allocatable .strtab, .shstrtab, .symtab sections.
But we are placing them after currently what creates a mix of
alloc/non-alloc sections and does not look normal.

Differential revision: https://reviews.llvm.org/D74756