install *.so in different paths for their types

Shared libraries are now installed to different directories depending on
their types.

* NDK libraries: /system/lib/ndk
* VNDK libraries: /system/lib/vndk
* VNDK-ext libraries: /system/lib/vndk-ext
* Framework-only libraries: /system/lib
* Vendor-only libraries: /vendor/lib
* Same-process HALs: /vendor/lib/sameprocess

In addition, a new module type vndk_ext_library is added. It is almost
identical to cc_shared_library but it introduces another attribute
'extends'. This is use to reference the vndk library that this vndk-ext
library is extending.

For example, in order to extend a vndk library libFoo:

cc_library {
  name: "libFoo",
  srcs: [...]
}
---------------------
vndk_ext_library {
  name: "libFoo-extended",
  srcs: [...]
  extends: "libFoo"
}

Then, libFoo will be installed as /system/lib/vndk/libFoo.so and
libFoo-extended will be installed as /system/lib/vndk-ext/libFoo.so.
Note that file name of the latter is libFoo.so, not libFoo-extended.so:
file name of an extending module is automatically set to that of the
extended module.

Bug: 33681361
Test: build & run. Libraries must be in the correct directories.
Change-Id: Ia1eb3940605d582a252c78da0f3a5b36fdab062b

cc/androidmk.go

@@ -156,6 +156,14 @@ func (library *libraryDecorator) AndroidMk(ctx AndroidMkContext, ret *android.An
 	}
 }
 
+func (vndkLibrary *vndkExtLibraryDecorator) AndroidMk(ctx AndroidMkContext, ret *android.AndroidMkData) {
+	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) error {
+		fmt.Fprintln(w, "LOCAL_EXTENDS_MODULE := ", vndkLibrary.properties.Extends)
+		return nil
+	})
+	vndkLibrary.libraryDecorator.AndroidMk(ctx, ret)
+}
+
 func (object *objectLinker) AndroidMk(ctx AndroidMkContext, ret *android.AndroidMkData) {
 	ret.Custom = func(w io.Writer, name, prefix, moduleDir string) error {
 		out := ret.OutputFile.Path()