Resolver: Split tests into multiple files

Try and make sense of the huge number of tests we have.

Rename tests so they have a consistent naming style.

Change-Id: I0c089d5945778a8718480a1a2f854435e7b0e79a
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/44162
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>

BUILD.gn

@@ -842,9 +842,11 @@ source_set("tint_unittests_core_src") {
     "src/intrinsic_table_test.cc",
     "src/program_builder_test.cc",
     "src/program_test.cc",
-    "src/resolver/resolver_test.cc",
+    "src/resolver/intrinsic_test.cc",
     "src/resolver/resolver_test_helper.cc",
     "src/resolver/resolver_test_helper.h",
+    "src/resolver/resolver_test.cc",
+    "src/resolver/validation_test.cc",
     "src/semantic/sem_intrinsic_test.cc",
     "src/scope_stack_test.cc",
     "src/symbol_table_test.cc",

src/CMakeLists.txt

@@ -470,11 +470,13 @@ if(${TINT_BUILD_TESTS})
     inspector/inspector_test.cc
     intrinsic_table_test.cc
     program_test.cc
-    resolver/resolver_test.cc
+    resolver/intrinsic_test.cc
     resolver/resolver_test_helper.cc
     resolver/resolver_test_helper.h
-    semantic/sem_intrinsic_test.cc
+    resolver/resolver_test.cc
+    resolver/validation_test.cc
     scope_stack_test.cc
+    semantic/sem_intrinsic_test.cc
     symbol_table_test.cc
     symbol_test.cc
     traits_test.cc