[CK_BUILDER] conv bwd weight testing (#3618)

* ck-builder: restructure testing conv

In order to prepare for bwd of conv testing, this commit moves some
files and types around so that we can reuse ckt::Args for both forward
and backwards convolution.

* ck-builder: decouple fwd_ck.hpp and fwd_reference.hpp from fwd.hpp

This will allow us to more easily include fwd.hpp from backwards
definitions, which is required for initializing bwd values.

* ck-builder: fix layout of test_ckb_conv_bwd_weight_xdl_cshuffle_v3

Turns out that the supplied layout isn't actually supported...

* ck-builder: ck and reference conv integration for bwd weight

* ck-builder: ck bwd weight execution test

* ck-builder: ckt::run support for ck-tile bwd weight

* ck-builder: ck tile bwd weight execution test

* ck-builder: extra debug printing in MatchesReference

* ck-builder: make ckt::run return RunResult

This type is more convenient than std::tuple, as it will allow us to
use google test matchers with this in the future.

* ck-builder: RunResult matcher

Using EXPECT_THAT(..., SuccessfulRun()) will generate a check and a nice error
message about how and why running an algorithm failed.

* ck-builder: doc fixes

* ck-builder: add missing headers

experimental/builder/test/unit_validation.cpp

@@ -296,5 +296,8 @@ TEST(MatchesReference, Incorrect)
     testing::StringMatchResultListener listener;
     EXPECT_TRUE(!ExplainMatchResult(MatchesReference(args, expected), actual, &listener));
 
-    EXPECT_THAT(listener.str(), StringEqWithDiff("1 tensors failed to validate"));
+    EXPECT_THAT(listener.str(),
+                StringEqWithDiff( //
+                    "1 tensors failed to validate\n"
+                    "    - a: 625/625 incorrect elements (~100%)"));
 }