[llvm-readelf][llvm-readobj] - Fix the indentation when printing dynamic tags.

This change is similar to one made for llvm-objdump in D72838.

llvm-readelf/llvm-readobj tools do not align the "Name/Value" column properly.
This patch adds a logic to calculate the size of indentation on fly
to fix such issues.

Differential revision: https://reviews.llvm.org/D72843