Fix UB in SIMD tests.

One of the SIMD tests attempted to left shift a value by 42, which
is UB when the left hand side is a 32 bit integer type.

This patch adjusts the test to use the value 4 instead of 42.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@342820 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed