`meson test` does not re-configure if there was a change in meson.build

Describe the bug
I added a new test() and tried to run it with meson test -C build --gdb mytest and it said No suitable tests defined.. Issuing ninja -C build caused it to re-configure and see the new test, then I could run meson test -C build --gdb mytest.

To Reproduce
Just add a new test in an already configured project with test() and try to run it with meson test -C build. Will provide example code later if necessary.

Expected behavior
meson test should re-configure if any meson.build file changed

system parameters

• Is this a cross build or just a plain native build (for the same computer)? native
• what operating system (e.g. MacOS Catalina, Windows 10, CentOS 8.0, Ubuntu 18.04, etc.) GNU Guix
• what Python version are you using: 3.8.2
• what meson --version 0.57.1
• what ninja --version if it's a Ninja build: 1.10.0

Start by reproducing meson test -C build after adding a new test() to an existing meson.build, then compare it with ninja -C build followed by the test command. Trace the meson test reconfiguration path; done means newly added tests are discovered without manually running Ninja.