[MC][ARM] make Thumb function also if type attribute is set

Make sure to set the bottom bit of the symbol even when the type
attribute of a label is set after the label.

GNU as sets the thumb state according to the thumb state of the label.
If a .type directive is placed after the label, set the symbol's thumb
state according to the thumb state of the .type directive. This matches
GNU as in most cases.

From: Stefan Agner <stefan@agner.ch>

This fixes:
https://bugs.llvm.org/show_bug.cgi?id=44860
https://github.com/ClangBuiltLinux/linux/issues/866

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D74927