[arm] Fix insn type of *thumb1_tablejump

[arm] Fix insn type of *thumb1_tablejump

*thumb1_tablejump had type "no_insn", which doesn't seems to correspond
to its documented use:

  an insn which does not represent an instruction in the final output,
  thus having no impact on scheduling.

Indirect jumps use the same instruction and have type "branch",
so the patch uses "branch" here too.

2019-09-17  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/arm/thumb1.md (*thumb1_tablejump): Change type from
	"no_insn" to "branch".

From-SVN: r275806