WebAssembly: remove 'external' from test

[jfb]

Summary

Linker testing was sad at seeing an unresolved external symbol. For now don't do that: it's valid but we're not playing with multi-file linking yet, and the LLVM tests are used as hacky sanity tests for single-file linking (the GCC torture tests are much better for this purpose). Another solution would be to use '.extern' to make the intent explicit (don't simple-file link this, there's an unresolved symbol), some assemblers use '.extern' while others ignore it, so we wouldn't really be inventing anything new.

[sunfish]

As we discussed on IRC, this test was using external intentionally, because that's a useful thing to test, and the problem is that these tests are being use to generate tests for other tools in which external doesn't make sense. I'm ok with this change as a workaround for now, but please add a TODO comment reminding us to go back and revisit this.

[jfb]

• Add fixme.

test/CodeGen/WebAssembly/offset-folding.ll

 ; RUN: llc < %s -asm-verbose=false | FileCheck %s
 
 ; Test that constant offsets can be folded into global addresses.
 
 target datalayout = "e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
-@x = external global [0 x i32]
+@x = global [0 x i32] zeroinitializer
 @y = global [50 x i32] zeroinitializer
 
 ; Test basic constant offsets of both defined and external symbols.
 
 ; CHECK-LABEL: test0:
 ; CHECK-NEXT: .result i32{{$}}
 ; CHECK-NEXT: i32.const $push0=, x+188{{$}}
 ; CHECK=NEXT: return $pop0{{$}}