t7508/12: set GIT_ADVICE=1 across all tests

The output of 'git status' changes depending on the availability of advice,
even though the messages are to stdout. Since this test script is all about
testing the output of 'git status' including the existence (or lack of)
these messages, set the GIT_ADVICE environment globally across the script.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>

Author: derrickstolee

t/t7508-status.sh

@@ -9,6 +9,10 @@ TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-terminal.sh
 
+# 'git status' output changes depending on the availability of advice,
+# so force its output to enable advice, even though it goes to stdout.
+GIT_ADVICE=1 && export GIT_ADVICE
+
 test_expect_success 'status -h in broken repository' '
 	git config --global advice.statusuoption false &&
 	mkdir broken &&

t/t7512-status-help.sh

@@ -17,6 +17,10 @@ TEST_PASSES_SANITIZE_LEAK=true
 
 set_fake_editor
 
+# 'git status' output changes depending on the availability of advice,
+# so force its output to enable advice, even though it goes to stdout.
+GIT_ADVICE=1 && export GIT_ADVICE
+
 test_expect_success 'prepare for conflicts' '
 	git config --global advice.statusuoption false &&
 	test_commit init main.txt init &&