Add EarlyModuleContext for LoadHookContext

Make LoadHookContext embed a new EarlyModuleContext instead of
BaseModuleContext to reduce its API surface in preparation for
moving it to run during parsing instead of mutators.

Test: m checkbuild
Change-Id: I1cd3ff3b636e7e24991a9184d7521903473e505a

android/hooks.go

@@ -26,8 +26,8 @@ import (
 // before the module has been split into architecture variants, and before defaults modules have
 // been applied.
 type LoadHookContext interface {
-	// TODO: a new context that includes Config() but not Target(), etc.?
-	BaseModuleContext
+	EarlyModuleContext
+
 	AppendProperties(...interface{})
 	PrependProperties(...interface{})
 	CreateModule(ModuleFactory, ...interface{}) Module