Reduce reserved size for DlExtTest.ReservedRecursiveTooSmall test

When built with clang-r353983, the ReservedRecursiveTooSmall test fail
due to the reserved memory is now large enough for android_dlopen_ext.
Reduce the reserved memory size to agree with ReservedTooSmall test.

Test: bionic-unit-tests
Bug: 126457671
Change-Id: I3e311a3f35b0de5d028fa1b9b3681d5ec32faee8
diff --git a/tests/dlext_test.cpp b/tests/dlext_test.cpp
index cace36c..f5e0c9c 100644
--- a/tests/dlext_test.cpp
+++ b/tests/dlext_test.cpp
@@ -372,12 +372,12 @@
 }
 
 TEST_F(DlExtTest, ReservedRecursiveTooSmall) {
-  void* start = mmap(nullptr, kLibSize/2, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  void* start = mmap(nullptr, PAGE_SIZE, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   ASSERT_TRUE(start != MAP_FAILED);
   android_dlextinfo extinfo;
   extinfo.flags = ANDROID_DLEXT_RESERVED_ADDRESS | ANDROID_DLEXT_RESERVED_ADDRESS_RECURSIVE;
   extinfo.reserved_addr = start;
-  extinfo.reserved_size = kLibSize/2;
+  extinfo.reserved_size = PAGE_SIZE;
   handle_ = android_dlopen_ext(kLibNameRecursive, RTLD_NOW, &extinfo);
   EXPECT_EQ(nullptr, handle_);
 }