[MIPS64] JNI Compiler: Sign-extend int function arguments

MIPS n64 ABI differs from arm64. Arguments smaller than the 8B stack
slot need to be sign-extended.

Use combination (lw,sd), instead of (lw,sw) for 4B values.

Change fixes software keyboard crash on mips64.

Bug: 21555893

(cherry picked from commit f652d605753f1387e7797461b47116c5dcdf928d)

Change-Id: I7574d37f6039e9e8c9e0047254be71d28d4c829a
diff --git a/test/MyClassNatives/MyClassNatives.java b/test/MyClassNatives/MyClassNatives.java
index 8b4a9a4..19c13f7 100644
--- a/test/MyClassNatives/MyClassNatives.java
+++ b/test/MyClassNatives/MyClassNatives.java
@@ -94,6 +94,9 @@
         float f4, int i5, float f5, int i6, float f6, int i7, float f7, int i8, float f8, int i9,
         float f9, int i10, float f10);
 
+    native static void stackArgsSignExtendedMips64(int i1, int i2, int i3, int i4, int i5, int i6,
+        int i7, int i8);
+
     static native double logD(double d);
     static native float logF(float f);
     static native boolean returnTrue();