Fix minor bugs in CtsAngleIntegrationHostTestCases

1. Fix the instrumentation target package name of the test app
com.android.angleintegrationtest.nativedrivercheck.

2. Remove the target_preparer entry in the AndroidTest.xml file.
There is already existing test code that does the "install app" job:

```
In CtsAngleDeveloperOptionHostTest.java:

installApp(ANGLE_DRIVER_TEST_APP)

```

Flag: TEST_ONLY
Test: atest CtsAngleIntegrationHostTestCases
Bug: b/357101639
Change-Id: Ied4b682563423ac72e9370114d9a7bd07ccf178e