Avoid modifying the PATH for the python test suites #1452

Job	Run time
Compile the UX-less version of the app on Nano S+ for performance tests	1m 34s
Compilation for X, S+, Stax and Flex (nanox, $NANOX_SDK)	1m 59s
Compilation for X, S+, Stax and Flex (nanosp, $NANOSP_SDK)	1m 59s
Compilation for X, S+, Stax and Flex (stax, $STAX_SDK)	2m 3s
Compilation for X, S+, Stax and Flex (flex, $FLEX_SDK)	2m 12s
Performance report	43s
Tests on mainnet (nanox)	41s
Tests on mainnet (nanosp)	44s
Tests with the Python library and legacy Bitcoin app	58s
Tests with the JS library	1m 23s
Tests on mainnet (stax)	51s
Tests on mainnet (flex)	46s
Tests for rust client library	1m 39s
Unit test	1m 27s
	18m 59s

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