[WebAssembly] Remove dead code from LEB compression pass. NFC.

[sbc100]

Summary

There are only certain relocation types that can exist in the
wasm code section and they are all LEB types. Remove the dead
code for handling the other (I32) reloc types.

[yurydelendik]

lgtm

[ruiu]

LGTM

wasm/InputChunks.cpp

static unsigned writeCompressedReloc(uint8_t *Buf, const WasmRelocation &Rel,
   case R_WEBASSEMBLY_TYPE_INDEX_LEB:
   case R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
   case R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
   case R_WEBASSEMBLY_MEMORY_ADDR_LEB:
     return encodeULEB128(Value, Buf);
   case R_WEBASSEMBLY_TABLE_INDEX_SLEB:
   case R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
     return encodeSLEB128(static_cast<int32_t>(Value), Buf);
-  case R_WEBASSEMBLY_TABLE_INDEX_I32:
-  case R_WEBASSEMBLY_MEMORY_ADDR_I32:
-    write32le(Buf, Value);
-    return 4;
   default:
-    llvm_unreachable("unknown relocation type");
+    llvm_unreachable("unexpected relocation type");
   }
 }
 
 static unsigned getRelocWidthPadded(const WasmRelocation &Rel) {
   switch (Rel.Type) {
   case R_WEBASSEMBLY_TYPE_INDEX_LEB:
   case R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
   case R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
   case R_WEBASSEMBLY_MEMORY_ADDR_LEB:
   case R_WEBASSEMBLY_TABLE_INDEX_SLEB:
   case R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
     return 5;
-  case R_WEBASSEMBLY_TABLE_INDEX_I32:
-  case R_WEBASSEMBLY_MEMORY_ADDR_I32:
-    return 4;
   default:
-    llvm_unreachable("unknown relocation type");
+    llvm_unreachable("unexpected relocation type");
   }
 }
 
 static unsigned getRelocWidth(const WasmRelocation &Rel, uint32_t Value) {
   uint8_t Buf[5];
   return writeCompressedReloc(Buf, Rel, Value);
 }