[X86][SSE] Pull out OR(EXTRACTELT(X,0),OR(EXTRACTELT(X,1),...)) matching code...

[X86][SSE] Pull out OR(EXTRACTELT(X,0),OR(EXTRACTELT(X,1),...)) matching code from LowerVectorAllZeroTest

Create a matchBitOpReduction helper that checks for the pattern with any opcode.

First step towards reusing this code to recognize other scalar reduction patterns.

llvm-svn: 359296