[binutils-gdb] Add current_regcache unit test

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 8248946cc5fd4522de630b9d86627af6e8fe0097 ***

Author: Yao Qi <yao.qi@linaro.org>
Branch: master
Commit: 8248946cc5fd4522de630b9d86627af6e8fe0097

Add current_regcache unit test

This patch adds a unit test to current_regcache, to make sure it is
correctly updated by get_thread_arch_aspace_regcache and
registers_changed_ptid.

gdb:

2017-05-09  Yao Qi  <yao.qi@linaro.org>

	* regcache.c [GDB_SELF_TEST]: Include selftest.h.
	(current_regcache_size): New function.
	(current_regcache_test): New function.
	(_initialize_regcache) [GDB_SELF_TEST]: Register the unit test.