Suppress GCC variable tracking warnings in debug builds

Add -fno-var-tracking-assignments flag for GCC debug builds to prevent
verbose "variable tracking size limit exceeded, retrying without" notes.

This particularly affects large test files like wpt_urlpattern_tests.cpp
that exceed GCC's variable tracking limits. The compiler automatically
retries without tracking, so these notes don't indicate actual problems,
but they create noise in build output.

The flag is applied only to Debug builds using a generator expression,
so it doesn't affect Release builds where variable tracking is already
disabled.

Author: claude

cmake/CompilerWarnings.cmake

@@ -124,6 +124,12 @@ function(ada_set_project_warnings target_name)
   elseif(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     target_compile_options(${target_name} PRIVATE ${GCC_WARNINGS_TO_USE})
 
+    # Suppress variable tracking notes in debug builds (prevents verbose "retrying without" messages)
+    # This affects large files like wpt_urlpattern_tests.cpp that exceed variable tracking limits
+    target_compile_options(${target_name} PRIVATE
+      $<$<CONFIG:Debug>:-fno-var-tracking-assignments>
+    )
+
     # Workaround for GCC poor AVX load/store code generation on x86
     # Skip this workaround when clang-tidy is enabled (it's Clang-based and doesn't support these flags)
     if(CMAKE_SYSTEM_PROCESSOR MATCHES "^(i.86|x86(_64)?)$" AND NOT ADA_ENABLE_CLANG_TIDY)