build: store global and project args per-machine even when not cross compiling

The problem is what happens in this case:
```meson
add_project_arguments('-DHOST', language : 'c', native : false)
add_project_arguments('-DBUILD', langauge : 'c', native : true)
```

The original meson behavior was that in an host == build configuration
only the `native : false` would be applied. This doesn't really make
sense as in that case the build machine is the host machine, so it is
both the native and non-native machine at once. We changed this so that
the both would be applied in a host == build configuration, but this is
a behavioral change, and needs to be reverted.

Fixes: #9037

mesonbuild/build.py

@@ -212,14 +212,10 @@ class Build:
         self.projects = {}
         self.targets: T.MutableMapping[str, 'Target'] = OrderedDict()
         self.run_target_names: T.Set[T.Tuple[str, str]] = set()
-        self.global_args: PerMachine[T.Dict[str, T.List[str]]] = PerMachineDefaultable.default(
-            environment.is_cross_build(), {}, {})
-        self.global_link_args: PerMachine[T.Dict[str, T.List[str]]] = PerMachineDefaultable.default(
-            environment.is_cross_build(), {}, {})
-        self.projects_args: PerMachine[T.Dict[str, T.Dict[str, T.List[str]]]] = PerMachineDefaultable.default(
-            environment.is_cross_build(), {}, {})
-        self.projects_link_args: PerMachine[T.Dict[str, T.Dict[str, T.List[str]]]] = PerMachineDefaultable.default(
-            environment.is_cross_build(), {}, {})
+        self.global_args: PerMachine[T.Dict[str, T.List[str]]] = PerMachine({}, {})
+        self.global_link_args: PerMachine[T.Dict[str, T.List[str]]] = PerMachine({}, {})
+        self.projects_args: PerMachine[T.Dict[str, T.Dict[str, T.List[str]]]] = PerMachine({}, {})
+        self.projects_link_args: PerMachine[T.Dict[str, T.Dict[str, T.List[str]]]] = PerMachine({}, {})
         self.tests: T.List['Test'] = []
         self.benchmarks: T.List['Test'] = []
         self.headers: T.List[Headers] = []