Fix bitrot in the libnativebridge tests.

- Bitrot 1: NativeBridge2Signal_test stopped working when version 3 was
  added in https://r.android.com/234059.

- Bitrot 2: The code path that PreInitializeNativeBridgeFail1_test
  tested was removed completely when missing app data directory was
  allowed in https://r.android.com/1208629, so delete the test.

- Use cc_test_library for the dynamic test libs so they are installed in
  the test directory rather than in system/lib(64).

- Use test_per_src since native_bridge.cc doesn't support reloading the
  native bridge implementation lib after unloading.

- Add a custom script to run the tests and a preupload check that the
  script is run. (Configuring atest for these tests still TBD in
  b/189484095 - test_per_src is a complication.)

Test: art/libnativebridge/tests/runtests.sh
Bug: 122710865
Bug: 189484095
Change-Id: Ib2b387e1d858127ca4bb44c548a5105ea8b838d8
diff --git a/libnativebridge/tests/NativeBridgeTest.h b/libnativebridge/tests/NativeBridgeTest.h
index cd0fd01..62509b8 100644
--- a/libnativebridge/tests/NativeBridgeTest.h
+++ b/libnativebridge/tests/NativeBridgeTest.h
@@ -27,6 +27,7 @@
 constexpr const char* kCodeCacheStatFail = "./code_cache/temp";
 constexpr const char* kNativeBridgeLibrary2 = "libnativebridge2-test-case.so";
 constexpr const char* kNativeBridgeLibrary3 = "libnativebridge3-test-case.so";
+constexpr const char* kNativeBridgeLibrary6 = "libnativebridge6-test-case.so";
 
 namespace android {
 
@@ -36,4 +37,3 @@
 };  // namespace android
 
 #endif  // ART_LIBNATIVEBRIDGE_TESTS_NATIVEBRIDGETEST_H_
-