xtensa: fix gas trampolines regression

xtensa: fix gas trampolines regression

Extra condition 'abs (addr - trampaddr) < J_RANGE / 2' for trampoline
selection results in regressions: when relaxable jump is little longer
than J_RANGE so that single trampoline makes two new jumps, one longer
than J_RANGE / 2 and one shorter, correct trampoline cannot be found.

Drop that condition.

2015-05-13  Max Filippov  <jcmvbkbc@gmail.com>
gas/
	* config/tc-xtensa.c (xtensa_relax_frag): Allow trampoline to be
	closer than J_RANGE / 2 to jump frag.

gas/testsuite/
	* gas/xtensa/trampoline.s: Add regression testcase.