Update spirv tools (#2246)

* Update known good SPIRV-Tools

* Update test expectations

Test/baseResults/spv.textureGatherBiasLod.frag.out

@@ -1,5 +1,4 @@
 spv.textureGatherBiasLod.frag
-Validation failed
 // Module Version 10000
 // Generated by (magic number): 80008
 // Id's are bound by 298

known_good.json

@@ -5,7 +5,7 @@
       "site" : "github",
       "subrepo" : "KhronosGroup/SPIRV-Tools",
       "subdir" : "External/spirv-tools",
-      "commit" : "bd0a2da946c3fb4c641acc4a0d53ee67653e200a"
+      "commit" : "4386ef4234e28f933412774b0ba718ae0e211333"
     },
     {
       "name" : "spirv-tools/external/spirv-headers",