linker: don't pass dlextinfo to dependent loads

Don't pass the parent load's dlextinfo to dependent loads, since this
causes the linker to try to load the dependencies using the same
addresses/relro/fds/etc as the main library, which is never going to
work. This was how it worked before ae69a95 which broke this.

Bug: http://b/23742664
Bug: http://b/20948231
Bug: http://b/20841817
Change-Id: I340ebae1127666d5c6c6f9c6521b89fb93f15bdd
diff --git a/tests/dlext_test.cpp b/tests/dlext_test.cpp
index f901708..44b899e 100644
--- a/tests/dlext_test.cpp
+++ b/tests/dlext_test.cpp
@@ -114,6 +114,10 @@
   fn f = reinterpret_cast<fn>(dlsym(handle_, "getRandomNumber"));
   ASSERT_DL_NOTNULL(f);
   EXPECT_EQ(4, f());
+
+  uint32_t* taxicab_number = reinterpret_cast<uint32_t*>(dlsym(handle_, "dlopen_testlib_taxicab_number"));
+  ASSERT_DL_NOTNULL(taxicab_number);
+  EXPECT_EQ(1729U, *taxicab_number);
 }
 
 TEST_F(DlExtTest, ExtInfoUseFdWithOffset) {
@@ -372,6 +376,10 @@
     fn f = reinterpret_cast<fn>(dlsym(handle_, "getRandomNumber"));
     ASSERT_DL_NOTNULL(f);
     EXPECT_EQ(4, f());
+
+    uint32_t* taxicab_number = reinterpret_cast<uint32_t*>(dlsym(handle_, "dlopen_testlib_taxicab_number"));
+    ASSERT_DL_NOTNULL(taxicab_number);
+    EXPECT_EQ(1729U, *taxicab_number);
   }
 
   void SpawnChildrenAndMeasurePss(const char* lib, bool share_relro, size_t* pss_out);