Support relative paths in android/run-checks.sh

Support relative paths in android/run-checks.sh

This patch updates the script to ensure that parameters
passed to the --ndk-dir and --adb option can contain relative
paths instead of absolute ones.

[Ted Mielczarek]

LGTM

https://breakpad.appspot.com/426003/diff/1/android/run-checks.sh
File android/run-checks.sh (right):

https://breakpad.appspot.com/426003/diff/1/android/run-checks.sh#newcode270
android/run-checks.sh:270: (cd "$1" &>/dev/null && pwd 2>/dev/null) || echo "$1"
Maybe this should just explicitly error instead?

[Mark Mentovai]

https://breakpad.appspot.com/426003/diff/1/android/run-checks.sh
File android/run-checks.sh (right):

https://breakpad.appspot.com/426003/diff/1/android/run-checks.sh#newcode261
android/run-checks.sh:261: # Convert a path to its absolute version (unless it
is invalid)
This only works on directories that exist. Document that. And name it
dir_absolute_path too, to make it somewhat self-documenting.

Or…

Make it smarter by splitting the argument into basename and dirname, doing the
cd on the dirname, and then appending the basename. Since this function will
ultimately be used to build an absolute path to a file, not a directory, that
will concentrate the logic here in this function, allowing absolute_command_path
to focus on other things.