Revert "tests/tcg/multiarch/Makefile.target: Disable run-gdbstub-sha1 test"

We won't attempt to run the test now it's gated on a newer version of
gdb.

This reverts commit a930cadd.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210108224256.2321-5-alex.bennee@linaro.org>

tests/tcg/multiarch/Makefile.target

@@ -54,9 +54,7 @@ run-gdbstub-sha1: sha1
 		--bin $< --test $(MULTIARCH_SRC)/gdbstub/sha1.py, \
 	"basic gdbstub support")
 
-# Disable this for now -- it provokes a gdb internal-error on
-# Ubuntu gdb 8.1.1-0ubuntu1.
-# EXTRA_RUNS += run-gdbstub-sha1
+EXTRA_RUNS += run-gdbstub-sha1
 endif