Fix get_device_api_level_inlines.h in versioner

This commit fixes an inline and non-inline mismatch error caused by
`get_device_api_level_inlines.h`.

Versioner includes both `android/api-level.h` and
`bits/get_device_api_level_inlines.h` in the test.  When __ANDROID_API__
is greater than or equal to __ANDROID_API_Q__, `android/api-level.h`
declares a non-inline `android_get_device_api_level()`.  On the
contrary, `bits/get_device_api_level_inlines.h` defines a static inline
`android_get_device_api_level()` function.  These conflicting
declarations result in compilation error.

This commit fixes the problem by guarding full
`get_device_api_level_inline.h` with
`#if defined(__BIONIC_GET_DEVICE_API_LEVEL_INLINE)` so that
`get_device_api_level_inline.h` can be no-op when it is not properly
included.

Note: This is not revealed until recently because API level 29 is added
in Mar 14 and the prebuilt binary for versioner hasn't been updated.

Test: ./bionic/tools/versioner/run_tests.py
Change-Id: Ia7d5fbdcaf3d98787e60780f6cff2a24016324f5