This CL moves the validation code to the val:: namespace. This makes it
clearer which instance of the Instruction and other classes are being
referred too.
Re-formatted the source tree with the command:
$ /usr/bin/clang-format -style=file -i \
$(find include source tools test utils -name '*.cpp' -or -name '*.h')
This required a fix to source/val/decoration.h. It was not including
spirv.h, which broke builds when the #include headers were re-ordered by
clang-format.
It is best to check the error messages of unit tests that fail
validation. This will ensure that a validation failure is due to what we
expect and not due to some secondary reason.
Updating SPIR-V Validator unit tests with error message checks.
According to the SPIRV Spec (2.16.1):
* There is at least one OpEntryPoint instruction, unless the Linkage
capability is being used.
* No function can be targeted by both an OpEntryPoint instruction and an
OpFunctionCall instruction.
Also updated unit tests to includ OpEntryPoint.
