ART: Use python as defined in env to fix build on some systems
Ensures the correct python version is used to prevent syntax errors

Change-Id: Ie57cf024341784284c2d2c5625c825f8b4544881
Partly fix art with sabermod 4.8

First error fixed - now there's another error:
F/art     (  604): art/runtime/well_known_classes.cc:118] Couldn't find method "nativeLoad" with signature "(Ljava/lang/String;Ljava/lang/ClassLoader;Ljava/lang/String;)Ljava/lang/String;"
But I have no idea how to fix that. I never used JNI and therefore don't know how it works.
The signature seems to be right as can be seen in runtime/native/java_lang_Runtime.cc => search for "NATIVE_METHOD".
4-byte align 64-bit values in Get/Set Double/Long for GCC 4.8.

Bug: 10837416
Change-Id: Ibb562407d81c2085666ae8824e7570f22e56eaa7