AAPT2: Allow compatible duplicate Attributes

If a resource XML file defines two compatible Attributes, they should
be merged without throwing an error. Ex:

<declare-styleable>
  <attr name="conflict" format="string" />
</declare-styleable>

<declare-styleable>
  <attr name="conflict" format="string|reference" />
</declare-styleable>

In this case, string|reference and string are the same, so these should
merge correctly.

Bug: 65699599
Test: make aapt2_tests
Test: make AaptBasicTest
Change-Id: I7b0f956d2332f7f0b458acd59ca0a606b2cfdf95
diff --git a/tools/aapt2/process/SymbolTable.cpp b/tools/aapt2/process/SymbolTable.cpp
index 3cae0e8..2e97a2f 100644
--- a/tools/aapt2/process/SymbolTable.cpp
+++ b/tools/aapt2/process/SymbolTable.cpp
@@ -243,7 +243,7 @@
   // Check to see if it is an attribute.
   for (size_t i = 0; i < (size_t)count; i++) {
     if (entry[i].map.name.ident == android::ResTable_map::ATTR_TYPE) {
-      s->attribute = std::make_shared<Attribute>(false, entry[i].map.value.data);
+      s->attribute = std::make_shared<Attribute>(entry[i].map.value.data);
       break;
     }
   }