Require file tests to specify a min-prelude (#5818)

Use `full.carbon` min-prelude for any tests using the full prelude. A
few tests were using it unnecessarily and are changed to a more minimal
one in the process.

Any test which does not include some min-prelude will now fail with an
error.

toolchain/check/testdata/interop/cpp/fail_fuzzing.carbon

@@ -2,6 +2,7 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/none.carbon
 // ARGS: --include-diagnostic-kind --fuzzing compile --no-prelude-import --dump-sem-ir-ranges=only --phase=check %s
 //
 // AUTOUPDATE