tests: Set up testdata path for continuous native tests.

continuous_native_tests expects the testdata under DATA/ in
continuous_native_tests.zip. This CL packs a copy of the testdata into
continuous_native_tests.zip as DATA/nativetest/recovery/testdata (via
LOCAL_PICKUP_FILES).

This CL also removes the extra copy for nativetest64. Testdata will
always stay at /data/nativetest/recovery/testdata, even for 64-bit
version. Otherwise we will unnecessarily get four copies (two for data/
and another two for DATA/).

Bug: 32123241
Test: mmma bootable/recovery && adb sync data. On bullhead,
    /data/nativetest/recovery_component_test/recovery_component_test works;
    /data/nativetest64/recovery_component_test/recovery_component_test works.
Test: m continuous_native_test; DATA/nativetest/recovery/testdata exists.

Change-Id: Ifefa0309de7af23c77654e8e450848ca2da218c2