Clarify error checking function names in the GLSL parser

Most error checking functions in ParseContext used to follow a format
like <property>ErrorCheck. Sometimes this function would check that
the node/value would have <property>, sometimes it would check that
the node/value would not have it, which was confusing. Change most of
these functions to use a lot more descriptive names, which clearly
communicate what they are checking for.

Also includes a bit of refactoring in constructorErrorCheck(), so that
the function only checks for errors rather than also setting the type
of the constructor node.

Also make TType::arraySize unsigned, and return a sanitized size from
checkIsValidArraySize() instead of using an output parameter.

BUG=angleproject:911
TEST=angle_unittests

Change-Id: Id9767b8c79594ad3f782f801ea68eb96df721a31
Reviewed-on: https://chromium-review.googlesource.com/367070
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/compiler/translator/ValidateOutputs.cpp b/src/compiler/translator/ValidateOutputs.cpp
index 29ca68d..9f5f8f5 100644
--- a/src/compiler/translator/ValidateOutputs.cpp
+++ b/src/compiler/translator/ValidateOutputs.cpp
@@ -60,7 +60,7 @@
     for (const auto &symbol : mOutputs)
     {
         const TType &type         = symbol->getType();
-        const size_t elementCount = static_cast<size_t>(type.isArray() ? type.getArraySize() : 1);
+        const size_t elementCount = static_cast<size_t>(type.isArray() ? type.getArraySize() : 1u);
         const size_t location     = static_cast<size_t>(type.getLayoutQualifier().location);
 
         ASSERT(type.getLayoutQualifier().location != -1);