Add support for fixed parameters in the register allocator.

runtime/vm/code_generator.cc

Index: runtime/vm/code_generator.cc
diff --git a/runtime/vm/code_generator.cc b/runtime/vm/code_generator.cc
index dd20c04d032da41cdb659abc8e820f88ec43825d..d006df3341093e55754b67383566213ca13ec5be 100644
--- a/runtime/vm/code_generator.cc
+++ b/runtime/vm/code_generator.cc
@@ -1332,9 +1332,8 @@ DEFINE_RUNTIME_ENTRY(OptimizeInvokedFunction, 1) {
     return;
   }
   if ((FLAG_optimization_filter != NULL) &&
-      (strncmp(function.ToFullyQualifiedCString(),
-               FLAG_optimization_filter,
-               strlen(FLAG_optimization_filter)) != 0)) {
+      (strstr(function.ToFullyQualifiedCString(),
+              FLAG_optimization_filter) == NULL)) {
     function.set_usage_counter(kLowInvocationCount);
     return;
   }