[AArch64] Prefer "mov" over "orr" to materialize constants.

This is generally more readable due to the way the assembler aliases
work.

(This causes a lot of test changes, but it's not really as scary as it
looks at first glance; it's just mechanically changing a bunch of checks
for orr to check for mov instead.)

Differential Revision: https://reviews.llvm.org/D59720

llvm-svn: 356954
diff --git a/llvm/test/CodeGen/AArch64/optimize-imm.ll b/llvm/test/CodeGen/AArch64/optimize-imm.ll
index f960a3a..711bad7 100644
--- a/llvm/test/CodeGen/AArch64/optimize-imm.ll
+++ b/llvm/test/CodeGen/AArch64/optimize-imm.ll
@@ -52,7 +52,7 @@
 ; a BIC.
 
 ; CHECK-LABEL: xor1:
-; CHECK: orr [[R0:w[0-9]+]], wzr, #0x38
+; CHECK: mov [[R0:w[0-9]+]], #56
 ; CHECK: bic {{w[0-9]+}}, [[R0]], w0, lsl #3
 
 define i32 @xor1(i32 %a) {