Add explicit dependency on v8_base

Add explicit dependency on v8_base

This is necessary in order to link v8_shell (for host) with the Android
toolchain.

Without it, the line in the makefile is:
$(builddir)/v8_shell: LD_INPUTS := $(OBJS) $(obj).host/v8/tools/gyp/libv8_snapshot.a $(obj).host/v8/tools/gyp/libv8_base.a

Now it appears as:
$(builddir)/v8_shell: LD_INPUTS := $(OBJS) $(obj).host/v8/tools/gyp/libv8_base.a $(obj).host/v8/tools/gyp/libv8_snapshot.a

and it successfully links.

BUG=
TEST=

Committed: https://code.google.com/p/v8/source/detail?r=11005

[Yaron, 2012-03-09 18:06:33]

We're currently trying to get chromium's unit_tests target to build for the
Android configuration. However, v8_shell fails to link without this change. It
appears to be a requirement of the linker included in the Android toolchain.

[Jakob Kummerow, 2012-03-12 10:24:00]

It's sad that this hack is necessary, but since you've added an explaining
comment, LGTM.

I'll land it for you.