[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.

Change-Id: I7574d37f6039e9e8c9e0047254be71d28d4c829a
3 files changed