cmd/compile/internal/types2: move a handful of tests

These tests belong into the fixedbugs directory.
This matches the go/types organization.
No changes to the code.

Change-Id: I36bcf70672d9ea5a40175c445e1d036c603ae76f
Reviewed-on: https://go-review.googlesource.com/c/go/+/312570
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>

diff --git a/src/cmd/compile/internal/types2/testdata/issue23203a.src b/src/cmd/compile/internal/types2/fixedbugs/issue23203a.src
similarity index 100%
rename from src/cmd/compile/internal/types2/testdata/issue23203a.src
rename to src/cmd/compile/internal/types2/fixedbugs/issue23203a.src

diff --git a/src/cmd/compile/internal/types2/testdata/issue23203b.src b/src/cmd/compile/internal/types2/fixedbugs/issue23203b.src
similarity index 100%
rename from src/cmd/compile/internal/types2/testdata/issue23203b.src
rename to src/cmd/compile/internal/types2/fixedbugs/issue23203b.src

diff --git a/src/cmd/compile/internal/types2/testdata/issue26390.src b/src/cmd/compile/internal/types2/fixedbugs/issue26390.src
similarity index 100%
rename from src/cmd/compile/internal/types2/testdata/issue26390.src
rename to src/cmd/compile/internal/types2/fixedbugs/issue26390.src

diff --git a/src/cmd/compile/internal/types2/testdata/issue28251.src b/src/cmd/compile/internal/types2/fixedbugs/issue28251.src
similarity index 100%
rename from src/cmd/compile/internal/types2/testdata/issue28251.src
rename to src/cmd/compile/internal/types2/fixedbugs/issue28251.src

diff --git a/src/cmd/compile/internal/types2/testdata/issue6977.src b/src/cmd/compile/internal/types2/fixedbugs/issue6977.src
similarity index 100%
rename from src/cmd/compile/internal/types2/testdata/issue6977.src
rename to src/cmd/compile/internal/types2/fixedbugs/issue6977.src