Revert "Make YAML quote forward slashes."

This reverts commit b86c16ad8c97dadc1f529da72a5bb74e9eaed344.

This is being reverted because I forgot to write a useful
commit message, so I'm going to resubmit it with an actual
commit message.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@344358 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/Tooling/DiagnosticsYamlTest.cpp

@@ -58,30 +58,30 @@ TEST(DiagnosticsYamlTest, serializesDiagnostics) {
   YAML << TUD;
 
   EXPECT_EQ("---\n"
-            "MainSourceFile:  'path/to/source.cpp'\n"
+            "MainSourceFile:  path/to/source.cpp\n"
             "Diagnostics:     \n"
             "  - DiagnosticName:  'diagnostic#1\'\n"
             "    Message:         'message #1'\n"
             "    FileOffset:      55\n"
-            "    FilePath:        'path/to/source.cpp'\n"
+            "    FilePath:        path/to/source.cpp\n"
             "    Replacements:    \n"
-            "      - FilePath:        'path/to/source.cpp'\n"
+            "      - FilePath:        path/to/source.cpp\n"
             "        Offset:          100\n"
             "        Length:          12\n"
             "        ReplacementText: 'replacement #1'\n"
             "  - DiagnosticName:  'diagnostic#2'\n"
             "    Message:         'message #2'\n"
             "    FileOffset:      60\n"
-            "    FilePath:        'path/to/header.h'\n"
+            "    FilePath:        path/to/header.h\n"
             "    Replacements:    \n"
-            "      - FilePath:        'path/to/header.h'\n"
+            "      - FilePath:        path/to/header.h\n"
             "        Offset:          62\n"
             "        Length:          2\n"
             "        ReplacementText: 'replacement #2'\n"
             "  - DiagnosticName:  'diagnostic#3'\n"
             "    Message:         'message #3'\n"
             "    FileOffset:      72\n"
-            "    FilePath:        'path/to/source2.cpp'\n"
+            "    FilePath:        path/to/source2.cpp\n"
             "    Replacements:    \n"
             "...\n",
             YamlContentStream.str());

unittests/Tooling/ReplacementsYamlTest.cpp

@@ -33,13 +33,13 @@ TEST(ReplacementsYamlTest, serializesReplacements) {
 
   // NOTE: If this test starts to fail for no obvious reason, check whitespace.
   ASSERT_STREQ("---\n"
-               "MainSourceFile:  '/path/to/source.cpp'\n"
+               "MainSourceFile:  /path/to/source.cpp\n"
                "Replacements:    \n" // Extra whitespace here!
-               "  - FilePath:        '/path/to/file1.h'\n"
+               "  - FilePath:        /path/to/file1.h\n"
                "    Offset:          232\n"
                "    Length:          56\n"
                "    ReplacementText: 'replacement #1'\n"
-               "  - FilePath:        '/path/to/file2.h'\n"
+               "  - FilePath:        /path/to/file2.h\n"
                "    Offset:          301\n"
                "    Length:          2\n"
                "    ReplacementText: 'replacement #2'\n"