Update to V8 with partial snapshots. This is taken from the partial_snapshot branch of V8.
diff --git a/test/cctest/test-regexp.cc b/test/cctest/test-regexp.cc
index b1ca45a..db312da 100644
--- a/test/cctest/test-regexp.cc
+++ b/test/cctest/test-regexp.cc
@@ -653,6 +653,8 @@
typedef RegExpMacroAssemblerX64 ArchRegExpMacroAssembler;
#elif V8_TARGET_ARCH_ARM
typedef RegExpMacroAssemblerARM ArchRegExpMacroAssembler;
+#elif V8_TARGET_ARCH_MIPS
+typedef RegExpMacroAssembler ArchRegExpMacroAssembler;
#endif
class ContextInitializer {