base/android: Handle JNI_OnLoad failures better

Just a tiny fix to follow the API contract.

Bug: None
Change-Id: I2ed632b45d802ddc100340121b7e29b37abc5198
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2560123Reviewed-by: Benoit L <lizeb@chromium.org>
Commit-Queue: Egor Pasko <pasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#831009}

base/android/linker/modern_linker_jni.cc

@@ -439,7 +439,7 @@ int LoadCreateSharedRelocations(const String& path, void* wanted_address) {
   }
 
   if (!CallJniOnLoad(handle))
-    return false;
+    return -1;
 
   return relro_fd;
 }