refactor: make disassembler optional

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

tests/meson.build

@@ -13,6 +13,12 @@ tests_sources = files(
 subdir('cpu')
 subdir('util')
 
+tests_cpp_args = []
+
+if get_option('disassembler')
+  tests_cpp_args += '-DDISASSEMBLER'
+endif
+
 catch2 = dependency('catch2', version: '>=3.4.0', static: true)
 catch2_tests = executable(
   'matar_tests',
@@ -21,6 +27,7 @@ catch2_tests = executable(
   link_with: tests_deps,
   include_directories: [inc, src],
   build_by_default: false,
+  cpp_args: tests_cpp_args
 )
 
 test('catch2 tests', catch2_tests)