codegen: do not modify caller's working directory

When changing directory to $ANDROID_BUILD_TOP, do so in a subshell
environment. This will leave the caller's working directory intact.

Test: manual (cd frameworks/base && source tests/Codegen/runTest.sh # afterwards, $(pwd) is still frameworks/base)
Change-Id: I6558f00a8912141f41c65426ba31c234fc9d63df
1 file changed