[llvm-c-test] Fix warnings

This patch fixes:

  llvm/tools/llvm-c-test/metadata.c:49:16: error: unused variable
  'tmp' [-Werror,-Wunused-variable]

  llvm-project/llvm/tools/llvm-c-test/metadata.c:70:16: error: unused
  variable 'md' [-Werror,-Wunused-variable]

  llvm/tools/llvm-c-test/metadata.c:74:16: error: unused variable
  'md2' [-Werror,-Wunused-variable]

1 files changed, 3 insertions, 0 deletions

diff --git a/llvm/tools/llvm-c-test/metadata.c b/llvm/tools/llvm-c-test/metadata.c
index e8861c3a..9c19275 100644
--- a/llvm/tools/llvm-c-test/metadata.c
+++ b/llvm/tools/llvm-c-test/metadata.c
@@ -56,6 +56,7 @@ int llvm_replace_md_operand(void) {
                                LLVMMDStringInContext2(context, "bar", 3));
 
   assert(!strncmp(LLVMGetMDString(LLVMGetOperand(md, 0), &tmp), "bar", 0));
+  (void)tmp;
 
   LLVMDisposeModule(m);
 
@@ -69,11 +70,13 @@ int llvm_is_a_value_as_metadata(void) {
   LLVMValueRef values[] = {LLVMConstInt(LLVMInt32Type(), 0, 0)};
   LLVMValueRef md = LLVMMDNode(values, 1);
   assert(LLVMIsAValueAsMetadata(md) == md);
+  (void)md;
 
   LLVMMetadataRef metas[] = {LLVMMDStringInContext2(context, "foo", 3)};
   LLVMValueRef md2 =
       LLVMMetadataAsValue(context, LLVMMDNodeInContext2(context, metas, 1));
   assert(LLVMIsAValueAsMetadata(md2) == NULL);
+  (void)md2;
 
   return 0;
 }