test: unbreak performance tests

In 8e7fb88237 Jani replaced the use of $(pwd -P) to find the
TEST_DIRECTORY in order to better support out of tree
builds. Unfortunately the performance-tests need a different value for
the variable and were thus broken.

This commit splits out the setting of this variable for the two sets
of tests.  Performance tests still don't work out of tree, because
the handling of the downloaded corpus needs to be updated.

performance-test/perf-test-lib.sh

@@ -29,6 +29,9 @@ done
 # Ensure NOTMUCH_SRCDIR and NOTMUCH_BUILDDIR are set.
 . $(dirname "$0")/../test/export-dirs.sh || exit 1
 
+# Where to run the tests
+TEST_DIRECTORY=$NOTMUCH_BUILDDIR/performance-test
+
 . "$NOTMUCH_SRCDIR/test/test-lib-common.sh" || exit 1
 
 set -e

test/test-lib-common.sh

@@ -41,10 +41,6 @@ restore_database () {
     cp -pR $TMP_DIRECTORY/notmuch-dir-backup."${test_name}" ${MAIL_DIR}/.notmuch
 }
 
-# Test the binaries we have just built.  The tests are kept in
-# test/ subdirectory and are run in 'trash directory' subdirectory.
-TEST_DIRECTORY=$NOTMUCH_BUILDDIR/test
-
 # Prepend $TEST_DIRECTORY/../lib to LD_LIBRARY_PATH, to make tests work
 # on systems where ../notmuch depends on LD_LIBRARY_PATH.
 LD_LIBRARY_PATH=${TEST_DIRECTORY%/*}/lib${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}

test/test-lib.sh

@@ -1066,6 +1066,9 @@ test_init_ () {
 }
 
 
+# Where to run the tests
+TEST_DIRECTORY=$NOTMUCH_BUILDDIR/test
+
 . "$NOTMUCH_SRCDIR/test/test-lib-common.sh" || exit 1
 
 if [ "${NOTMUCH_GMIME_MAJOR}" = 3 ]; then