Reuse `os` variable in AllocateTarget; NFC

GitOrigin-RevId: 8fbfc92a5cef5e709ca47742e7bf11035607abcc
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 793a471..8df5cb7 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -595,13 +595,13 @@
     }
 
   case llvm::Triple::spir: {
-    if (Triple.getOS() != llvm::Triple::UnknownOS ||
+    if (os != llvm::Triple::UnknownOS ||
         Triple.getEnvironment() != llvm::Triple::UnknownEnvironment)
       return nullptr;
     return new SPIR32TargetInfo(Triple, Opts);
   }
   case llvm::Triple::spir64: {
-    if (Triple.getOS() != llvm::Triple::UnknownOS ||
+    if (os != llvm::Triple::UnknownOS ||
         Triple.getEnvironment() != llvm::Triple::UnknownEnvironment)
       return nullptr;
     return new SPIR64TargetInfo(Triple, Opts);
@@ -611,7 +611,7 @@
         Triple.getVendor() != llvm::Triple::UnknownVendor ||
         !Triple.isOSBinFormatWasm())
       return nullptr;
-    switch (Triple.getOS()) {
+    switch (os) {
       case llvm::Triple::WASI:
         return new WASITargetInfo<WebAssembly32TargetInfo>(Triple, Opts);
       case llvm::Triple::Emscripten:
@@ -626,7 +626,7 @@
         Triple.getVendor() != llvm::Triple::UnknownVendor ||
         !Triple.isOSBinFormatWasm())
       return nullptr;
-    switch (Triple.getOS()) {
+    switch (os) {
       case llvm::Triple::WASI:
         return new WASITargetInfo<WebAssembly64TargetInfo>(Triple, Opts);
       case llvm::Triple::Emscripten: