clang-tidy: wrap test_utils.hpp in cpp

Introduced a temporary wrapper `.cpp` file that includes
`test_utils.hpp` to allow clang-tidy to analyze the header
in the correct compilation context.

clang-tidy was failing to resolve includes like `actions/action.hpp`
when run directly on `test_utils.hpp`, due to missing include path
context in the compilation database. This is a known limitation when
analyzing header files outside of a translation unit.

By wrapping the header in a `.cpp` file and running clang-tidy on
that instead, we ensure that all include paths and macros are
correctly applied, resolving false-positive errors and improving
static analysis reliability.

Change-Id: I9a72d14ab844c0b53eebea6229e0bc22ff8aa273
Signed-off-by: Jayanth Othayoth <ojayanth@gmail.com>
diff --git a/phosphor-regulators/test/meson.build b/phosphor-regulators/test/meson.build
index 3db580f..20fa19d 100644
--- a/phosphor-regulators/test/meson.build
+++ b/phosphor-regulators/test/meson.build
@@ -24,6 +24,7 @@
     'sensor_monitoring_tests.cpp',
     'sensors_tests.cpp',
     'system_tests.cpp',
+    'test_utils.cpp',
     'write_verification_error_tests.cpp',
     'actions/action_environment_tests.cpp',
     'actions/action_error_tests.cpp',