JIT: Use rsb and shift in easy multiply.

For easy multiplication using reverse subtract (when
lit is 2^n-1) use the barrel shifter for rsb.

This improves arithmetic performance for code executing
in Dalvik. E.g String.hashCode.

Change-Id: I3bba4e24c6333f9910c24c4bd3effaf5c4dd9cab
Signed-off-by: Patrik Ryd <patrik.ryd@stericsson.com>
Disable -Xjnigreflimit.

This was supposed to help find bugs, but in practice (unlike the
locale reference limit and the pinned array limit) doesn't. What it
does do is cause well-behaved code to fail if its allocation rate
is high. This has caused trouble for both audio and graphics code
running on eng builds.

Bug: 7903975
Change-Id: If475cb51c9cab13270a83a60d6d0aecfab758e88