Ensure that Module resource is managed locally wrt. a unit test case

Author: VyacheslavLevytskyy

llvm/unittests/Target/SPIRV/SPIRVAPITest.cpp

@@ -36,7 +36,9 @@ class SPIRVAPITest : public testing::Test {
                const std::vector<std::string> &AllowExtNames,
                const std::vector<std::string> &Opts) {
     SMDiagnostic ParseError;
-    M = parseAssemblyString(Assembly, ParseError, Context);
+    LLVMContext Context;
+    std::unique_ptr<Module> M =
+        parseAssemblyString(Assembly, ParseError, Context);
     if (!M) {
       ParseError.print("IR parsing failed: ", errs());
       report_fatal_error("Can't parse input assembly.");
@@ -48,9 +50,6 @@ class SPIRVAPITest : public testing::Test {
     return Status;
   }
 
-  LLVMContext Context;
-  std::unique_ptr<Module> M;
-
   static constexpr StringRef ExtensionAssembly = R"(
     define dso_local spir_func void @test1() {
     entry: