ANDROID: 16K: Only madvise padding from dynamic linker context

Only preform padding advise from the execution context on bionic's
dynamic linker. This ensures that madvise() doesn't have unwanted
side effects.

Also rearrange the order of fail checks in madvise_vma_pad_pages()
in order of ascending cost.

Bug: 330117029
Bug: 327600007
Bug: 330767927
Bug: 328266487
Bug: 329803029
Change-Id: I3e05b8780c6eda78007f86b613f8c11dd18ac28f
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>