AAPT2: Ensure style strings are always first in StringPool

Move the styled strings to a separate section of the StringPool so
that sorting can never mess up the order of Styles.

Bug: 63570514
Test: make aapt2_tests
Change-Id: Id2ce1355b92be1bb31ce0daa7e54ae9b5b6c2ffe
diff --git a/tools/aapt2/ResourceUtils.cpp b/tools/aapt2/ResourceUtils.cpp
index 6e6a2ba..f193fe0 100644
--- a/tools/aapt2/ResourceUtils.cpp
+++ b/tools/aapt2/ResourceUtils.cpp
@@ -700,7 +700,7 @@
           spans++;
         }
         return util::make_unique<StyledString>(dst_pool->MakeRef(
-            style_str, StringPool::Context(StringPool::Context::kStylePriority, config)));
+            style_str, StringPool::Context(StringPool::Context::kNormalPriority, config)));
       } else {
         if (type != ResourceType::kString && util::StartsWith(str, "res/")) {
           // This must be a FileReference.