[WebAssembly] Add a comment about why v128.const test was disabled (NFC)

llvm-svn: 353236

Author: aheejin

llvm/test/MC/Disassembler/WebAssembly/wasm.txt

@@ -33,6 +33,8 @@
 # CHECK: i64.trunc_sat_f64_u
 0xFC 0x07
 
+# FIXME Disabled temporarily due to failures in clang-ppc64be-linux and
+# clang-s390x-linux bots
 # C HECK: v128.const 50462976, 117835012, 185207048, 252579084
 0xFD 0x02 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F