[GlobalISel] Bump CallLoweringInfo::OrigArgs initial size to 32. NFC.

We spend some time during sqlite3 compilation regrowing this vector,
bump it up to avoid this.

Gives around 1-2% improvement in codegen-only time for sqlite3 at -O0.

llvm/include/llvm/CodeGen/GlobalISel/CallLowering.h

@@ -104,7 +104,7 @@ public:
     ArgInfo OrigRet;
 
     /// List of descriptors of the arguments passed to the function.
-    SmallVector<ArgInfo, 8> OrigArgs;
+    SmallVector<ArgInfo, 32> OrigArgs;
 
     /// Valid if the call has a swifterror inout parameter, and contains the
     /// vreg that the swifterror should be copied into after the call.