Make CompilationSupport use the specified CcToolchainProvider even if…

… the :cc_toolchain implicit attributes are not available.

RELNOTES: Banana.
PiperOrigin-RevId: 221268738

src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java

@@ -725,19 +725,12 @@ private CompilationSupport(
     this.outputGroupCollector = outputGroupCollector;
     this.objectFilesCollector = objectFilesCollector;
     this.usePch = usePch;
-    // TODO(b/62143697): Remove this check once all rules are using the crosstool support.
-    if (ruleContext
-            .attributes()
-            .has(CcToolchain.CC_TOOLCHAIN_DEFAULT_ATTRIBUTE_NAME, BuildType.LABEL)
-        || ruleContext.attributes().has(":j2objc_cc_toolchain", BuildType.LABEL)) {
-      if (toolchain == null) {
-        toolchain =  CppHelper.getToolchainUsingDefaultCcToolchainAttribute(ruleContext);
-      }
-      this.toolchain = toolchain;
-    } else {
-      // Since the rule context doesn't have a toolchain at all, ignore any provided override.
-      this.toolchain = null;
+    if (toolchain == null && ruleContext.attributes().has(
+        CcToolchain.CC_TOOLCHAIN_DEFAULT_ATTRIBUTE_NAME, BuildType.LABEL)) {
+      toolchain =  CppHelper.getToolchainUsingDefaultCcToolchainAttribute(ruleContext);
     }
+
+    this.toolchain = toolchain;
   }
 
   /** Builder for {@link CompilationSupport} */