unit-test: Increase available debug information for test builds

Configuring `-Og` helps ensure `abi-dumper` has all the information it
would like for ABI analysis.

```
    ...
    [18/39] Generating abi-dump with a custom command
    Detect public symbols
    Reading debug-info
    WARNING: incompatible build option detected: -O0 (required -Og for better analysis)
    ...
```

Change-Id: Ia4d2add17a1e65bb480cb7003597af62c8e47bc2
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/scripts/unit-test.py b/scripts/unit-test.py
index 815dd17..4221d0f 100755
--- a/scripts/unit-test.py
+++ b/scripts/unit-test.py
@@ -906,7 +906,10 @@
             "-Dwarning_level=3",
         ]
         if build_for_testing:
-            meson_flags.append("--buildtype=debug")
+            # -Ddebug=true -Doptimization=g is helpful for abi-dumper but isn't a combination that
+            # is supported by meson's build types. Configure it manually.
+            meson_flags.append("-Ddebug=true")
+            meson_flags.append("-Doptimization=g")
         else:
             meson_flags.append("--buildtype=debugoptimized")
         if OptionKey("tests") in meson_options: