Change RemoteServiceServlet so gwt.codeserver.port works with more subclasses.

In many subclasses of RemoteServiceServlet, the doGetSerializationPolicy()
method is overridden so that it doesn't call super. As a result, setting
gwt.codeserver.port has no effect. To avoid this, I moved the calling code
into getSerializationPolicy(), which is a final method.

A subclass can still disable fetching serialization policies from
the code server by overriding getCodeServerPolicyUrl() to return 0,
but this won't happen by accident.

Change-Id: Ib47db371b78eabb1a139948744279b36aa306bc1
Review-Link: https://gwt-review.googlesource.com/#/c/2360/

Review by: mdempsky@google.com
Moves c.g.gwt.logging to common StackTraceDeobfuscator.

Change-Id: I44bee6a3abdf550831f6f9263a8c6e3c807ca063
Review-Link: https://gwt-review.googlesource.com/#/c/2300/

Review by: skybrian@google.com
RequestFactoryGenerator generated invalid java classes.

In some cases RequestFactoryGenerator generated classes that implemented the same generic
interface twice with different generic parameters. For example:

class X extends AbstractRequest<ResultType>
implements InstanceRequest<BarProxy, ResultType> { ... }

where AbstractRequest is defined in the library as follows:

class AbstractRequest<X> implements InstanceRequest<BaseProxy, X> {... }

Although the code is not valid java the GWT compiler would ignore the error and generate
working code; but newer versions of the JDT reject the code.

The change here is to add a type argument to AbstractRequest:
AbstractRequest<P extends BaseProxy, X> … implements InstanceRequest<P, X>

Change-Id: Ib9a604ef63f05bbecd8bfed60255f74682607fcc
Review-Link: https://gwt-review.googlesource.com/#/c/2370/

Review by: skybrian@google.com
Removes obsolete way of identifying test classes in module.

Actually, I hope this is obsolete because I couldn't find any use cases.

Change-Id: I765ac2274336e78707c1975b1eb6fab6ac27d30b
Review-Link: https://gwt-review.googlesource.com/#/c/2371/

Review by: skybrian@google.com
Refactors c.g.gwt.logging to use SerializableThrowable.

Change-Id: Ifeee26a9b36cbe40bd1cf0942da8fae39179e985
Review-Link: https://gwt-review.googlesource.com/#/c/2310/

Review by: skybrian@google.com
Refactors c.g.gwt.junit to use common SerializableThrowable & StacktraceDeobfuscator.

- Gets rid of duplicate code in junit for deobfuscation of stack traces
- Improves the messaging of unserializable exceptions
- Minor improvements to the reporting of test infra failures

Change-Id: I1e1021bc99ac88ea6d9d47c3d23c83e79a896213
Review-Link: https://gwt-review.googlesource.com/#/c/2290/

Review by: skybrian@google.com