Fix system_test app path and adb failed issue

[Why] App path is incorrected for Linux in system_path. Fix system_test cannot find executable app on Linux. Fix adb command executed failed.

[How] Set corrected app path for Linux when run system_test. Correct input arguments of subprocess.check_output.

Description

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Fixes #

General Checklist:

Please ensure the following points are checked:

[x] My code follows the coding style
[x] I have reviewed file licenses
[x] I have commented any added functions (in line with Doxygen)
[x] I have commented any code that could be hard to understand
[x] My changes do not add any new compiler warnings
[x] My changes do not add any new validation layer errors or warnings
[x] I have used existing framework/helper functions where possible
[x] My changes do not add any regressions
[x] I have tested every sample to ensure everything runs correctly
[x] This PR describes the scope and expected impact of the changes I am making

Note: The Samples CI runs a number of checks including:
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- [x] My changes build on Windows, Linux, macOS and Android. Otherwise I have documented any exceptions

Sample Checklist

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[x] I have tested the sample on at least one compliant Vulkan implementation
[x] If the sample is vendor-specific, I have tagged it appropriately
[x] I have stated on what implementation the sample has been tested so that others can test on different implementations and platforms
[x] Any dependent assets have been merged and published in downstream modules
[x] For new samples, I have added a paragraph with a summary to the appropriate chapter in the samples readme
[x] For new samples, I have added a tutorial README.md file to guide users through what they need to know to implement code using this feature. For example, see conditional_rendering
[x] For new samples, I have added a link to the Antora navigation so that the sample will be listed at the Vulkan documentation site

KhronosGroup / Vulkan-Samples