Compile libart.so and libart-compiler.so with 2MB section alignment.

Adds the appropriate linker flags for libart and libart-compiler to have
2MB section alignment. This allows the executable segment of these
libraries to be backed by transparent hugepages on supporting systems.

Bug: 158135888
Test: Verified ELF format

Change-Id: Ia6455418cf1fdd3a1a98d662bf381db4b58b8536
diff --git a/compiler/Android.bp b/compiler/Android.bp
index d1eae50..cb47d77 100644
--- a/compiler/Android.bp
+++ b/compiler/Android.bp
@@ -206,6 +206,7 @@
     defaults: [
         "libart-compiler-defaults",
         "dex2oat-pgo-defaults",
+        "art_hugepage_defaults",
     ],
     codegen: {
         arm: {