Revert to using OBJROOT as the tmpdir for Windows compiles

Author: owenv

Sources/SWBWindowsPlatform/Specs/WindowsCompile.xcspec

@@ -17,8 +17,8 @@
         Type = Compiler;
         BasedOn = "default:com.apple.compilers.llvm.clang.1_0";
         EnvironmentVariables = {
-            "TEMP" = "$(CACHE_ROOT:default=$(OBJROOT))";
-            "TMP" = "$(CACHE_ROOT:default=$(OBJROOT))";
+            "TEMP" = "$(OBJROOT)";
+            "TMP" = "$(OBJROOT)";
         };
         Name = "Apple LLVM Windows";
         Description = "Apple LLVM Windows compiler";

Tests/SWBBuildSystemTests/ClangExplicitModulesTests.swift

@@ -1419,6 +1419,7 @@ fileprivate struct ClangExplicitModulesTests: CoreBasedTests {
                             buildConfigurations: [TestBuildConfiguration(
                                 "Debug",
                                 buildSettings: [
+                                    "OBJROOT": tmpDir.join("objroot").str,
                                     "PRODUCT_NAME": "$(TARGET_NAME)",
                                     "CLANG_ENABLE_MODULES": "YES",
                                     "_EXPERIMENTAL_CLANG_EXPLICIT_MODULES": "YES",