all.sh: be more conservative when cleaning up CMake artefacts

Only delete things that we expect to find, to avoid deleting other
things that people might have lying around in their build tree.
Explicitly skip .git to avoid e.g. accidentally matching a branch
name.

tests/scripts/all.sh

@@ -149,7 +149,13 @@ cleanup()
 {
     command make clean
 
-    find . -name yotta -prune -o -iname '*cmake*' -not -name CMakeLists.txt -exec rm -rf {} \+
+    # Remove CMake artefacts
+    find . -name .git -prune -o -name yotta -prune -o \
+           -iname CMakeFiles -exec rm -rf {} \+ -o \
+           \( -iname cmake_install.cmake -o \
+              -iname CTestTestfile.cmake -o \
+              -iname CMakeCache.txt \) -exec rm {} \+
+    # Recover files overwritten by in-tree CMake builds
     rm -f include/Makefile include/mbedtls/Makefile programs/*/Makefile
     git update-index --no-skip-worktree Makefile library/Makefile programs/Makefile tests/Makefile
     git checkout -- Makefile library/Makefile programs/Makefile tests/Makefile