Remove ad-hoc tab_width / indent_size handling from editorconfig-core

[monnier]

Remove from editorconfig-core.el code that sets tab_width from indent_size and vice-versa, since that's better done (and is done) later in editorconfig.el.

[xuhdev]

Test failed:

195/202 Test #195: unset_indent_size_ML .............................***Failed  Required regular expression not found. Regex=[^[
]*indent_size=unset[ 	

]*tab_width=unset[ 	

]*$
]  0.03 sec

indent_size=unset