Fixed issue where GradientDrawable would fail inflation

with invalid angle parameters

Previously, GradientDrawable would fail xml parsing if
an angle measurement was not a multiple of 45 and the type
of gradient is linear. Restore the original behavior to only
verify the angle measurement only if the type is linear
instead of verifying this requirement for all gradient types.

Removed restriction that radii must be non-negative as
subsequent logic in GradientDrawable already clamps the radius
to valid parameters.

Bug: 130309904
Test: Updated tests in CtsGradientDrawableTest
Change-Id: Ib1b3a0bb80639ddc00be7e630c62e781dfa6d9cf