Parallelize src/test/test into chunks.

First, we introduce a flag to teach src/test/test to split its work
into chunks.  Then we replace our invocation of src/test/test in our
"make check" target with a set of 8 scripts that invoke the first
8th of the tests, the second 8th, and so on.

This change makes our "make -kj4 check" target in our hardened
gitlab build more than twice as fast, since src/test/test was taking
the longest to finish.

Closes 40098.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/test/unittest_part8.sh b/src/test/unittest_part8.sh
new file mode 100755
index 0000000000..7fea9c9c7f
--- /dev/null
+++ b/src/test/unittest_part8.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+"${abs_top_builddir:-.}/src/test/test" --fraction 8/8