[llvm][TextAPI/MachO] Update variable names in unit tests. (NFC)

This changes the variables names to match the TBD version.

Differential revision: https://reviews.llvm.org/D73326
diff --git a/llvm/unittests/TextAPI/TextStubV4Tests.cpp b/llvm/unittests/TextAPI/TextStubV4Tests.cpp
index dc50e51..c007482 100644
--- a/llvm/unittests/TextAPI/TextStubV4Tests.cpp
+++ b/llvm/unittests/TextAPI/TextStubV4Tests.cpp
@@ -434,14 +434,14 @@
 }
 
 TEST(TBDv4, Swift_2) {
-  static const char tbd_v1_swift_2[] = "--- !tapi-tbd\n"
+  static const char tbd_v4_swift_2[] = "--- !tapi-tbd\n"
                                        "tbd-version: 4\n"
                                        "targets: [  x86_64-macos ]\n"
                                        "install-name: Test.dylib\n"
                                        "swift-abi-version: 2\n"
                                        "...\n";
 
-  auto Result = TextAPIReader::get(MemoryBufferRef(tbd_v1_swift_2, "Test.tbd"));
+  auto Result = TextAPIReader::get(MemoryBufferRef(tbd_v4_swift_2, "Test.tbd"));
   EXPECT_TRUE(!!Result);
   auto File = std::move(Result.get());
   EXPECT_EQ(FileType::TBD_V4, File->getFileType());
@@ -545,7 +545,7 @@
 }
 
 TEST(TBDv4, MalformedFile3) {
-  static const char tbd_v1_swift_1_1[] = "--- !tapi-tbd\n"
+  static const char tbd_v4_swift_1_1[] = "--- !tapi-tbd\n"
                                          "tbd-version: 4\n"
                                          "targets: [  x86_64-macos ]\n"
                                          "install-name: Test.dylib\n"
@@ -553,7 +553,7 @@
                                          "...\n";
 
   auto Result =
-      TextAPIReader::get(MemoryBufferRef(tbd_v1_swift_1_1, "Test.tbd"));
+      TextAPIReader::get(MemoryBufferRef(tbd_v4_swift_1_1, "Test.tbd"));
   EXPECT_FALSE(!!Result);
   auto errorMessage = toString(Result.takeError());
   EXPECT_EQ("malformed file\nTest.tbd:5:20: error: invalid Swift ABI "