[llvm] Remove unused using decls (NFC) (#138386)

Author: kazutakahirata

llvm/unittests/Support/FormatVariadicTest.cpp

@@ -13,7 +13,6 @@
 #include "gtest/gtest.h"
 
 using namespace llvm;
-using ::testing::HasSubstr;
 
 // Compile-time tests templates in the detail namespace.
 namespace {

llvm/unittests/Support/YAMLIOTest.cpp

@@ -25,7 +25,6 @@ using llvm::yaml::Hex8;
 using llvm::yaml::Input;
 using llvm::yaml::isNumeric;
 using llvm::yaml::MappingNormalization;
-using llvm::yaml::MappingTraits;
 using llvm::yaml::Output;
 using llvm::yaml::ScalarTraits;
 using ::testing::StartsWith;

llvm/unittests/Target/SPIRV/SPIRVAPITest.cpp

@@ -22,8 +22,6 @@
 #include <string>
 #include <utility>
 
-using ::testing::StartsWith;
-
 namespace llvm {
 
 extern "C" LLVM_EXTERNAL_VISIBILITY bool

llvm/unittests/Target/SPIRV/SPIRVConvergenceRegionAnalysisTests.cpp

@@ -24,9 +24,6 @@
 #include "gtest/gtest.h"
 #include <queue>
 
-using ::testing::Contains;
-using ::testing::Pair;
-
 using namespace llvm;
 using namespace llvm::SPIRV;
 

llvm/unittests/tools/llvm-exegesis/RISCV/TargetTest.cpp

@@ -27,7 +27,6 @@ namespace {
 
 using testing::IsEmpty;
 using testing::Not;
-using testing::NotNull;
 
 class RISCVTargetTest : public RISCVTestBase {
 protected: